Is income tax a revenue-based tax?

• The term "revenue tax" really has little/no meaning. Different writers, economists, would happen to define it in different ways. (I've never really heard the term, it sounds a bit whacky.) Note that "definition" questions are largely meaningless. You're literally just "re-asking" what we will "decide this means". If you say "rent and groceries are included in revenue tax calculations" and I say "rent and groceries are not included in revenue tax calculations" - so what? I could just choose a different word for my usage, and/or you could choose a different word for your usage.

• One big thing you are missing. Self-employed people of course also only pay tax on profits. Just like a company. "A self-employed person" is just a business. If a client has me build a fancy machine and they pay me $200k and the machine costs me $100k, obviously I only pay tax on $100k. (Thank God!) So there's no difference at all, in that sense, between how a small business (ie "a human") and a company are taxed.

• If your contention is that people "should" be allowed to first subtract the cost of rent/groceries. I'm all for it! :) But the immediate objection is, those costs have nothing to do with the "business". See? The company making cars, obviously deducts the cost of steel and paint. But of course, they can't deduct the cost of groceries! Similarly, someone arguing against you, would say that for a person working at McDonalds, the cost of their groceries has nothing to do with that "business". I would note that many people indeed do believe that humans who are employed, should, be able to deduct the cost of regular commuting, since indeed that is 100% entirely part of the "business of having that job" (whereas, as I mention, "groceries" say just has nothing to do with it.

• Recall too that many think corporate taxes are completely stupid. Consider any company. It makes a million in profit. Pretend for a sec there are no corporate taxes. What happens to the million dollars? It goes to Mars? Of course not, corporations don't exist, they're a fiction, the entire million dollars goes to one person or another! (The owners, workers, shareholders - whatever.) And then of course obviously it is taxed. Corporate tax is utterly pointless, it probably results in less tax take for a government.

Yes, this is the way it works. You may feel that's unfair, but consider that corporations and business actually can't pay taxes. At the end of the day, it's always a real human paying the tax anyway, even if a business is the vehicle by which the tax is collected.

Historically, it was done this way because it makes the most sense. If you tax people on savings (income minus expenses), then you're penalizing people who save. If you tax a business on revenue, you'll end up taxing businesses that have a lot of revenue, but not a lot of profit. Those business might still be adding value to society - just not earning tons of profit at that moment.