Are you nitpicking an ally for using "exclusive" instead of "principal"?

MapleEngineer doesn't actually know for sure that he has never been attracted to a trans woman. So it's important to correct him when he says he has an exclusive sexual interest in cis-women.

Is that your point? That failing to acknowledge the nuance that sexuality exists on a spectrum must be addressed confrontationally because it's erasure?

Transphobia and homophobia are too often literally (yes, I mean literally) beaten into men. We have to work to unlearn it. If an ally says he wouldn't be able to keep it up if he learned the woman he was courting was assigned male at birth, believe him, but don't discount him as an ally. Imo your efforts are better spent combating active transphobia than policing your allies. If their terminology hurts you, suggest better ways to articulate their points but do it collaboratively instead of confrontationally.

Just my two cents.