I think there are a lot of very "modern day" issues that are in conflict with the collective societal experience until very recently. Can an individual determine their own gender when historically it's bestowed upon you by your society. With a few exceptions, like the Castrati singers of Italy (eunuchs castrated before puberty to create singers with a man's frame and lungs and a boy's voicebox) gender and gender roles have been pretty much locked in by your sex. Sexual orientation was a separate concept, whereas the plethora of genders some want society to accept are a hybrid of the two.
My personal guess is it's the societal equivalent of a fad and won't last for long before until it's pared back again. It reminds me of the feminist fad of hyphenated last names for children that was briefly popular. It's a way to show how progressive you are, but it's so cumbersome it collapses under it's own weight pretty quickly.