There was actually a scientific study which found that homophobes find gay porn arousing. I can’t remember who did it or what the specifics are, but… yeah.
I wouldn’t stay friends with people like that, to be honest. I mean, I know it can be difficult when they’re entrenched in your life and your friend group, but seriously, there is no room for bigots in my life nor probably in yours. I say kick ‘em out!