However I don’t see why genders are necessary. We are all unique human beings and there’s no need to label everyone to a specific gender.

And if many people (specially, even if not exclusively, in a certain country whose name I’ll avoid mentioning) didn’t have as their favorite passtime “kill the freak”, where “freak” is anyone not belonging to their narrow definition of acceptability, difference would truly be unremarkable. However, reality doesn’t seem to be working well for those folks, and they need a way to identify each other to provide community and to feel less alone and, maybe, to defend each other.