Answered on Quora.
I suppose most straight men must be homophobes then if that is true.
A recent study showed straight men some sort of depictions of gay behavior (perhaps gay porn?) and measured the levels of disgust they experienced. I am not sure how they measured the disgust levels. Then they exposed these men to other things that most people think are disgusting. They found that straight men were more disgusted and repulsed by gay sex than they were by the sight of maggots. Maggots! That’s a pretty extreme level of revulsion.
What we don’t know is if this revulsion is inborn somehow or if it is learned behavior. I suspect it may be learned.