I think the only thing that bothers me about this counter is that transfems in denial do commonly identify as femboys to avoid acknowledging they are trans, whereas a trans man femboy has already transitioned and thus is definitionally no longer in denial and in fact has overcome denial to transition and live as a trans man. These are two different situations, the reasons for skepticism when encountering an “eggy” but self-identified cis femboy who insists they are not trans don’t apply to the trans man femboy, who is clearly not in denial by already going against the grain of society by having transitioned.

That said, I think it’s a much better argument to simply assert the pragmatic value of respecting someone’s self-identity, regardless of whether we think that self-identity is accurate or not (i.e. whether we think that person might be in denial or not).

A good example is Finnster, a femboy Twitch streamer who for a long time was speculated to be an egg. The debate raged on about whether he was actually trans, and this naturally brought up conversations about respecting someone’s self-identity. I still think even though Finnstser later came out as trans (thus maybe vindicating the “he’s an egg” crowd), it doesn’t mean we should think it was wrong for respecting his identity prior to his coming out. If he claimed he was a cis man, that’s what you respect whether you are skeptical that is actually his identity or not. This is a bit like the pronouns issue: you just respect the pronouns someone chooses, regardless of whether you think they suit the person or not.

Whether someone’s self conception of their gender identity is accurate is unrelated and essentially separate from the practical social etiquette of respecting self-identification.