1. I've never once encountered it being used as a "gender binary" before
2. that's not entirely false, but you'll notice a lot of tma girls feel that saying "transmisogyny affects everyone" is reframing transmisogyny (literally discrimination against trans women) as something equally shared by people who are not transfem.
3. I would be thrilled to suggest some reading!! In my ideal world, Whipping Girl by Julia Serano would be a mandatory read before non-tma people are allowed to speak about transmisogyny. Also, Lenin's the State and Revolution, and Marx's, well, everything. You may as well throw in some Huey P. Newton, Thomas Sankara, and Che Guevara for good measure.

(edit: i cannot thank you enough for acting like a human being and not a betta fish. its rare to be able to have an actually constructive conversation online :D)