Can you articulate a little?
Well, there's the Kinsey Scale and it's speculated that a lot of folks are somewhat bi, but due to all the social pressure and taboos, they suppress their gay side. It's speculated quite a lot that the reason some guys find thoughts of sex with guys so "vile" as opposed to just not being interested, is because they're afraid they'll like it and that entails a lot of things they've been conditioned to believe are just horrible. That's why the guys aren't good-looking in straight porn. If a guy starts finding himself turned on by the guy, he'll get that revulsion feeling.
Imagine a world where only straight is acceptable. If you were bi but just a little bit gay, it's easier to just be straight and suppress any gay feelings. So the only people who actually act on it and come out are the guys who are really, REALLY gay on the Kinsey Scale and not very straight at all. Some gay guys have never been with a woman and a woman's body is just really foreign to them (unlike a straight guy who is familiar with the male body, genitals, etc.). So I think some of them react that way because it just represents the unknown and there is just no way to explore it in a non-sexual way.
I don't have that reaction anymore because I started to become aware there were guys out there, who were actually quite hot, who have vaginas. I gradually got over my revulsion reaction to vaginas when I realized I could explore something like that as part of someone I'm actually attracted to. I used to ponder what it might feel like but I knew I never wanted to just experiment. There was just way too much baggage. I knew I couldn't feel romantic or sexual feelings for a woman--performance anxiety (how do I get it up if she's not turning me on?), one-sided feelings (the thought of hurting her because she might be into me but I won't be into her), just off the top of my head--all kinds of anxiety attached to it.