I am a pansexual trans/gender-fluid person

Gender and sexuality are a spectrum. Many people do not identify solely as male or female or solely as straight, gay or bisexual. There's quite a bit of room in between and around these terms. This necesitates more diversity of language when talking about one's gender or sexuality.

1. The difference between the terms bisexual and pansexual will differ depending on who you talk to. Pansexuality is the attraction to those on any part of gender spectrum, where as bisexualuality is the attration to both men and women. I suspect some folks using the term bisexual to describe themselves would also fall into the pansexual group as well, they just choose the more well known word.
2. Gender fluid does not mean that an individual doesn't want to be identified as a man or woman, in fact, the fluidity may very well be between being a man and woman. Gender fluidity doesn't imply a lack of gender, just that the gender can change. Agender, nongendered, genderless and genderfree actually do mean someone doesn't identify with any gender. As for the reason why there are so many terms? Transexual and transgender people are still not as accepted as other groups in the population at large. A lack of visibility and wide acceptance has made it so no one term is the dominant one for those who don't identify with the binary system.

Regarding question 1:

I think it's a matter of carefully reading the definitions. Bisexual means to be attracted to both men and women. Pansexual means to be attracted to people regardless of sex or gender identity.

To illustrate the difference, let's use food (because it's more relatable). Suppose you like pizza and pasta specifically then you could say you like both of those foods (possibly for different reasons). You could also like pizza and pasta because they are Italian food, you don't care about their difference, the mere fact that it's Italian does it for you.

The first example could be compared to bisexuality, they like both men and woman, possibly for different reasons. The term pansexual emphasises that they like both without emphasis on the gender. Think of the statement 'I like all Italian food', if you consider pizza and pasta Italian, then you like both of the specific examples. Having said that, the first is a subset of the latter. All pansexuals are also bisexual, but not all bisexuals have to be pansexuals.

Regarding question 2:

You already mentioned the term community, which is a good start for an answer. The community, in this case, is not organised like a government with one view point. To compare it with politics: take conservatives in the UK, they have mostly the same view points and are pressured to follow the party line.

Now look at the broader community, all conservatives in the world, they you could identify many sub-communities (the Conservative Party in the UK, the Republicans in the US, and so on for all the different countries, perhaps even multiple communities for a single country). As an outsider, two conservatives are just two conservatives, but on closer inspection they might turn out to have widely varying views.

The same goes for the LGBTQ community (or any other group of people defined by one thing: men, women, Americans, politicians, environmentalists, liberals, children, the elderly). In fact, I think you'll have difficulty finding any subset of people defined by one thing who almost unanimously agree on anything (why that is might be better suited for psychology.se, biology.se, or philosophy.se but even then you might not get all of them to agree on one answer ;) ).

I want to specifically address the first question in a way that it hasn't been yet.

Q 1. What is the difference between a bisexual and a pansexual?

Bisexualism works only in a context where gender is binary. It assumes that people are only one of two possible genders—and that if you are bisexual you are attracted to both. But gender neutrality eliminates this dichotomy altogether.

(Note, too, that the distinction we now make between sex and gender is something only relatively recent.)

There are people who positively identify as gender-neutral (or as a non-binary gender). They do not consider themselves to be either gender. And while some may identify with various components on a sliding scale or spectrum (with one gender at one end and another gender at the other end), others consider themselves to have no gender identity at all, and still others consider themselves to have an identity that is simply "outside" any such binary scale.

In other words, some people who are gender neutral reject not only two possible genders but also the idea of a defining spectrum between two genders. (At least with respect to themselves.)

From an interesting article called "10 things you always wanted to know about being non-binary but were afraid to ask":

If you're looking at gender on a spectrum from male to female, non-binary could be anywhere outside of that spectrum [emphasis mine] or in between the male and female.

So, coming back to pansexualism, it may be somewhat misleading to say that somebody who is pansexual is attracted to all people "regardless of where they fit on a spectrum" (unless you also include everybody who isn't on that spectrum). Instead, I would say that they are simply attracted to people period, regardless of gender identity or non-identity.

---

Here is some additional information, as pulled from comments.

Although Dictionary.com says that a bissexual is attracted to people of various gender identities, both Merriam-Webster and Oxford continue to explicitly use a binary definition for the word. At least traditionally, a bisexual is attracted to both men and women. But (by some definitions), they would not be attracted to somebody who doesn't identify as male or female.

Practically speaking, bisexualism might amount to the same thing as pansexualism. But still, there is a logical distinction between "I like all colours" and "colour is irrelevant."

The definition of pansexual provided in the question states (the emphasis is mine) that: "Pansexual people may refer to themselves as gender-blind, asserting that gender and sex are not determining factors in their romantic or sexual attraction to others."

Somebody who is colour blind is literally not influenced by the choice of those colours they can't distinguish—except intellectually. That's what's meant by "gender blind" when it comes to pansexuality. Bisexuals can differentiate between genders (although they are attracted to both); but pansexuals simply don't differentiate between them at all (aside from intellectually).

To reuse an analogy from a different answer, I like steak and I like pasta. But when I go to a restaurant that has both on the menu, I decide which of those I want to eat on that particular night—which one I'm more in the mood for. However, for somebody without taste buds (somebody who is "taste blind") the flavour of those two menu items will have no bearing on their choice. For them, based on taste alone, the two are indistinguishable, and they might as well be contemplating the same thing. They will make their decision based on other factors (price, calories, size, and so on).

Similarly, consider a bisexual who's presented with a choice between a man and a woman. While they are attracted to both, they might be feeling more partial to one gender. It likely won't be the only factor in their choice of partner, but it will be at least a factor.

For a pansexual, who is "gender blind," it won't be a factor at all. They won't feel any more partial to a particular gender than any other at any given time, simply because it's not part of their perception. They are simply unaware of gender in any way—aside from intellectually. For them, their choice in partner is only (and always) about all of the non-gender factors.

---

As for the second question, this culture, and the terminology behind it, is so new that language and attitudes haven't yet had time to "shake out" into a cohesive consensus yet. That there is no agreement comes down to the timing of adoption.

(It was only in 2017 that both The Chicago Manual of Style and the Associated Press Stylebook acknowledged the use of they and their (and even themself) as an acceptable form of gender-neutral third-person pronoun if required—but in particular when used in the context of people who use it as part of their identify as having a non-binary gender.)

The other answers are well-taken. To attempt a tl;dr:

Q1. What is the difference between a bisexual and a pansexual?

The people? Probably nothing. But the difference between the terms 'bisexual' and 'pansexual' is that the former implicitly assumes two genders ('binary gender') or attraction to only two genders while the latter implies that there are more (possibly many more) than 'male' and 'female'. People who identify as pansexual may not have issues with bisexuals per se but probably consider their own terminology more inclusive of the genderqueer.

Q2. Why is there no agreement in the LGTBQ community for a single, simple term to express this gender and sexual preference?

1st, because people disagree about language choices all the time for no good reason at all. All the moreso when so many neologisms are dealing so closely with identity, sexuality, and politics. 2nd, because 'the LGTBQ community' is an expression, not an actual gang that has regular conferences with a steering committee to hash out things in the interim. 3rd, because those terms, especially as self-applied, are not precisely overlapping and do not imply a new set third gender but an openness to either conceiving of more than two or personally ignoring them, whatever and however many they are.

Q2. Why is there no agreement in the LGTBQ community for a single, simple term to express this gender and sexual preference?

A2. Because the LGTBQ is not a single speech community, that's why.

A speech community -- a bunch of people who talk (mostly) with one another -- is where agreements on single terms take place subliminally, and they have already taken place in the various real speech communities that constitute the membership of a brand-new sociopolitical merger so diverse that we need a five-letter acronym for it.

All over the world there are local L,G,T,B, and Q speech communities (sometimes not formally united, or simply not socially connected, into LGTBQ. Yet.) And they have been there for a long time. Many speak English. They have their own speech terms and their own meanings to go with them and their own histories and mythologies. These things don't blend together coherently very fast, especially under social pressure.

So it's unlikely that there are -- or even could be -- any single, simple terms so early. At this stage of development the norm is evanescent pansemantic trans/meaning-fluid terms.

The difference between Pansexual and Bisexual can be explained like this.

Not all heterosexuals focus on lust when selecting a spouse. For some people, hetero, gay and pan, the emphasis is on being in love, and in a committed "forever" relationship. Many do not consumate their relationships sexually until vows are exchanged. People who are head over heels in love, may glimpse the Pan reality... Would you be less in love if your special darling was born a different gender?

By comparison, many people seek sexual relationships... or relationships that begin with sex. For these people, regardless of sexual orientation; desire, attraction and lust, are what it's all about. The physicality is important. Sometimes gender, colour, stature, size, clothing, muscle tone and even hairlessness can be some of the physical attributes that are judged in the selection of a partner. What prospective mates physically look like, is a huge priority. Bisexual people are sexually attracted to/by either/both/all genders.

Pan people are far less likely to be put off someone because of any physical trait, including a lack of genitalia.

• Bisexuality sensu lato (in the broad sense) means that one is sexually attracted to both males and females; it makes no distinction as to whether or not one is sexually attracted to persons who are neither male nor female.
  • Bisexuality sensu stricto (in the narrow sense) means that one is sexually attracted to males and females, but not to non-male non-female persons.
  • Pansexuality means that one is sexually attracted to persons of all genders.

If gender is regarded as a spectrum, with more possible values than just MALE and FEMALE, a pansexual person would be bisexual senso lato, due to being sexually attracted to both males and females, but would not be bisexual senso stricto, due to also being attracted to non-male non-females.

If gender is regarded as strictly binary, with the only possible values being MALE and FEMALE, the distinction between the two subcategories of bisexuality sensu lato disappears, and bisexuality and pansexuality become synonymous.