Why do some words containing a form of “philia” have it at the beginning and some have it at the end?

There are words like “philosophy”, “philology”, “philanthropy”; these have a form of “philia” at the beginning. Why don’t these words have it at the end?

Also, there are words like “haemophilia”, “hydrophilia”, “paedophilia”; these have a form of “philia” at the end. Why don’t these words have it at the beginning?

Why don’t all words with a form of “philia” have it on the same side? What is the rule for deciding if it goes to the beginning or the end of the word?