This is (usually) the result of years of not being to openly label yourself, hiding who you are, and feeling alone and not part of a broader community.

Just like a compressed spring will then expand after being let go before returning to a more balanced state, when society slowly gave queer people the space to at least exist openly, people started looking really deeply at "who they are" and "what communities do I belong to" and "how do I find what I want in a sea of diversity" which in turn gave rise to surprisingly specific microlabeling.

The tendency is for this to tone down, with broader categories. But who knows, we can't really predict language and societal change like that.