Same reason fat acceptance is- because lazy ass fuckers want extra oppression points so they can pretend their failure of a life is not entirely their fault. This non binary bullshit is just bullshit unless you’re intersex, which is like 0.05% of the population or something. If you weren’t born with recognizable genitalia, sure, I’ll accept you’re literally non binary. Other than that you’re make or female, whether you’re cis or trans. As you point out there are actual sexual orientation/gender identity minorities, but fats ruin absolutely everything and need to take things to an extreme to feel like it’s not their fault that other people with legitimate obstacles are still more successful than them.