I don't know who the specific individuals are, however, so if anyone has some context, I'd also like to know more. But just going from context provided by OP who shared this screengrab, the photos are actually of cis men, not trans men. The post itself never actually claims otherwise, but is cleverly worded in such a way as to bait out transphobes who will emerge to voice their own bigotry without considering how incorrect it is.

TBH, the top-level comment I have trouble parsing, seems to be a general disbelief to the idea that trans men could exist. The one replying to it claims that they can "still see the female shaped heads" even though the subjects of the photos were not AFAB to begin with. Despite the assertion that they're not bigoted, they're only seeing what they "want" to see, which is the presence of some inherent difference, characterized by a false understanding of gender presentation. And the third and final visible comment below that says all it needs to say, I think.

The joke is that these are all cisgender men. Transphobes are stupid.