steepholm

You could even have quite a strong degree of gobsmackedness without getting anywhere near transphobia. It would of course imply that he was cis-centric not to have picked up on the multiple earlier clues, but that's quite understandable (as is Dil's not getting how clueless he is).

I imagine homophobia is in there as well -- his fear of being gay due to having been attracted to someone with a penis.