i purposefully try not to follow the online trans discourse because it's asinine to me that the bits i end up seeing seem to boil down to whether or not transphobes take trans men's masculinity into account when they're transphobic to us with the only two options being "they don't" ("trans men are seen as intrinsically unable to be masculine because they're seen as women") and "they do in a bad way" ("people hate trans men's masculinity because they're seen as women"). i think both are wrong. when someone says "a man should be able to take a hit", it's not a good thing to say about someone, but they're saying it because men are supposed to be stronger than women. they're also usually saying it in the context of a man being unable to take a hit. masculinity is taken into account in a good way precisely to exclude people from it. it's not a "mark" like femininity, someone with some form of it is instead implicitly compared to the idea of the "real man" because "a few bad apples spoil the bunch"
trans men are no different. when transphobes say that we only transition due to internalized misogyny or whatever, the equation going on in their heads is "being a woman objectively sucks, no one would want to be a woman + being a man is objectively better, everyone in their right mind would want to be a man + girls have done boy stuff despite patriarchy since time immemorial, so trans men are on the whole stupid". like nsambu za suekama explained, anti-transmasculinity is the "trojan horse" for transmisogyny. you can't get "so, since you were born a boy, you don't really experience misogyny" without "misogyny defines the experience of girls". the latter sentiment, when taken as "misogyny is intrinsic" instead of "misogyny is imposed", works in combination with masculinity being exclusive to give transphobes the impression that trans men's transness must be contingent on misogyny - since misogyny is intrinsic, our "born womanhood" must be the defining factor of any possible gender-related feeling or decision we could have. this contributes both to our erasure and the vilification of trans women at the same time
the problem is that the construction of "woman = victim man = perpetrator" makes it easy to assume that the only way you can talk about oppression is through cultural shorthand designating "oppression" (ie "woman"), it's an acknowledgement of oppression only for the sake of justifying putting people into boxes so they can be easier to understand according to an arbitrary set of rules on how the world "should" work. this makes it super easy to paint essentialism in seemingly progressive language. reducing us to "confused girls" is more than anything binary reification - they care about the idea of a "confused girl" (who more often than not is also white in the western context), not actual trans men, otherwise they'd be making noise about stuff like this. using our birth assignment to explain our oppression primarily on that basis is essentially doing the same thing - especially since a lot of what we get can be easily connected to the flack men who are seen as insufficiently masculine including in terms of appearance get - even if it comes with accurate assessments.
i'm not denying what we face has a lot to do with how "the female body" is perceived, let alone how women as a whole are treated, this is solely about rhetoric/framing. the solution isn't to look at it through what positionality should theoretically indicate, but attribute + positionality. trans men aren't oppressed for being men because cis men aren't oppressed for their gender. we also aren't oppressed for being women because we aren't women. we, like all other marginalized men, are oppressed for being "fake" men. imo anti-transmasculinity is best understood as anti-effeminacy
i'd put it this way: men, masculine people, and people perceived that way are expected to use the "grown man" inside them to suppress their internal "little girl". trans men, being at the very least seen as masculine, are subject to this. because we're also trans, we're at the same time judged on the basis of the harm our "grown man" is perceived as doing to our "little girl". this can function as crocodile tears at the crier's own expectations ("trans men have internalized misogyny") or assumptions of selfishness and arrogance ("trans men are misogynists") because "grown man harming a little girl" is culturally coded as the epitome of evil. it can also be questioning our gender or assuming we don't know what we're doing whenever even a slight indication of the girl shows up (including stuff like not wanting to go bald, which many cis men don't either) because do we really want to be men if we don't fully suppress her ("faggots aren't men")? if "grown man" and "little girl" can't exist side-by-side, we can't exist
anyways please read suekama's theory of racial-class paternalism