HII RIPPER THANK YOU BROTHER ;^)

As for your answer: Randy holds deep contempt for feminine or otherwise non-conforming men. To him, they represent weakness, failure, and everything he despises about his own fractured identity and upbringing. He sees effeminate men as pathetic, repulsive, and emasculating, direct triggers for his internalized homophobia.

You pretty much clocked it that living with Abe has only deepened this disgust. Randy tolerates Abe & his smothering weirdness out of a sense of familial ownership [i.e. "this is my fucked-up father figure"], but he not so secretly loathes the effeminacy. It's a constant low-level humiliation that Randy endures while asserting dominance in other ways [ignoring boundaries, using the house for his crimes, etc.]

Due to Randy's taste, feminine or flamboyant men don’t register as sexually viable to him; they're more likely to provoke irritation, mockery, or violent dismissal. He might even see them as "worse than women" because they had the chance to be real men and failed. In rare cases where a more non-conforming man crosses his path, Randy would probably enjoy breaking them even more sadistically as punishment for embodying the weakness and vulnerability he hates in himself and in Abe.

In short: Randy's ideal man is a strong, stoic, masculine figure he can temporarily submit to physically before violently dominating and eradicating. Anything softer, campier, or visibly queer-coded reads as weakness and betrayal in his eyes. Abe is simply the uncomfortable exception he's forced to live with.