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, which is already implying that trans women can't "really" experience misogyny (and what they get is because "they put it on themselves"), works in combination with masculinity being exclusive to give transphobes the impression that trans men's transness must be contingent on misogyny - "real men" don't have these problems, so our "born womanhood" must be the defining factor of any possible gender-related feeling or thought we could have. this contributes both to our erasure and the vilification of trans women at the same time
the problem is that how we talk about masculinity makes it hard to actually talk about masculinity. for other marginalized men, there's always a third element which makes it easier to talk about the ways someone deviate from the "real man" standard. even lesbians usually articulate lesbophobia on the basis of being women who are attracted to women rather than just attracted to women, where gay men talk about homophobia in terms of our attraction and the gendered assumptions that come with it rather than men who are attracted to men. you can't do this with trans men without regarding us as either wholly like cis men or wholly like women. from there, 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, including putting gates around "who should be facing what kind of oppression" by creating false dichotomies like the one i mentioned in the first paragraph.
the fundamental error is in thinking of oppression as being "oppressed for x" rather than a multilayered and differing depending on where we see it. 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. i'm not saying that what we face has nothing to do with our birth assignment, this is solely about rhetoric/framing. the solution isn't to look at it through what our birth assignment 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 anything from being gnc to not wanting to go bald) 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
wouldn't be surprised if this description resonated with masculine women and even non-trans male/masc effeminate men & people who've experienced life that way as well. i believe that the root of anti-transmasculinity is anti-effeminacy and that, despite differences in societal treatment, both "masculine women" and "feminine men" represent the same existential fear. anyways please read suekama's theory of racial-class paternalism