I think it makes to sense to consider the term "AMAB" to be a transmisogynistic slur at this point.
It is a term that is pretty much always used with transfems in mind. Even though 99% of "AMAB" people are cis men and 100% of cis men were "AMAB", the term does not convey "cis men plus some other tiny groups included on a technicality", but rather specifically focuses your attention on the alleged similarities between cis men and transfems.
For instance, a phrase like "men's attitudes towards women" hints that men are generally misogynistic, whereas "AMAB attitudes towards women" suggests that transfems specifically are no different from cis men in their misogyny. The act of co-categorisation is in itself a political position.
I am only comfortable hearing "AMAB" from other transfems, and even then only if I trust that they understand it in the same way I do. Hearing it from anyone else is like a disorienting jolt or a slap in the face, barely different from the T-slur.
i think theyfab is closer to a slur than amab but transfeminists use it often. (for reference i think both are bad)
I mean, I don't say that word personally, but I don't think it's comparable because transfems saying that are punching up, but people using "AMAB" to refer to transfems are punching down. There is such a thing as a gender hierarchy, and transfems are right at the bottom.
In addition, that word is not used to refer to they/them users who were "AFAB" in general, it's specifically a reference to a type of non-binary person with whom we are all familiar, who weaponises their AGAB because (whether consciously or subconsciously) they know it confers privileges in queer spaces.
Transfeminists who use that word are criticising the fact that these people implicitly misgender themselves in order to reap the social rewards that come from doing so, something that transfem non-binary people are simply unable to do.
