As does the Disney corporation. And the Catholic Church. What's your point?
I assume that Lucy_Bella is quoting someone else (w/o attribution?) here:
Why not go all the way and discuss crossdressing in terms of the 4 humors?
We live in a society in which not only the gender binary but also the traits conventionally associated with the two genders are assumed to be as unchanging and intrinsic to reality as the Pauli exclusion principle. Since the "experts" are also members of this society, they are going to classify "gender-variant" behavior in ways that don't challenge the paradigm of binary gender and gender traits and force behavior that does challenge that paradigm into categories that don't. (And since they are mostly from the most privileged segments of society, their interest in maintaining their privilege also leads them to support the status quo.)
The only place one can hope for any alternative way of framing gender-binary-challenging behavior is with people who actually who actually live it, because they're the only ones who have among their interests one that _isn't_ in the direction of the status quo.
We saw this with gays and lesbians. Back when I was a child, the "experts" pretty uniformly agreed that homosexuality was a disorder and a perversion needing either cure or suppression. It was not the "experts", but the gays and lesbians themselves that challenged this, against enormous resistance from the "experts" and leaders.
It's been a similar story with sexism and racism -- the "experts" generally defined things in terms that justified the status quo, and it has always been left to the oppressed people themselves to come up with alternate framings of things.
For that matter, there are trans people who are challenging the idea that trans people are _necessarily_ people who are "transitioning to the other sex".





