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.
The problem is people adopting medical terms for social commentary. Hell, even in a physician setting I would raise an eyebrow if I saw AMAB/AFAB because even then they just have a section asking you to describe your gender identity/status
