I think this is an important point, you don’t have to look far on the internet to see instances pop up either unfortunately. Pretty much any community that used to fit under a label now fits under several and most of them have arguments about whether all those sub-units get to lay claim to the base identity anymore.
I don’t think it has to be that way, that there is a logic in having hierarchical labels that go from umbrella terms to very specific (sometimes profoundly individual) labels -or more correctly series of labels. I’d like to think that by the time someone’s managed to modify a “base” identity like feminist with five adjectives denoting a narrower and narrower pool of qualities they possess they’ve developed the ability to suss out who is really an outsider in a space and/or conversation and whether that potential outsider has a perspective that is useful, enlightening or meaningful in some way. This is possibly a depressingly optimistic thought.