Even if what you’re implying was true, (I have no idea and make no claims) that still wouldn’t change the fact that there is a real, fundamental separation of the human race into male and female genders.

Yes, there are aspects of ‘cultural gender’ which have certain roles, conventions, or physical presentations assigned to them, and we can subvert those if we so choose to.

I don’t know why people who support the right of people to present as they wish take it to the point of denying that there is something more fundamental than social interactions and conventions which differentiates men from women.