I think most people have a visceral aversion to the idea of having sex with someone they find sexually unappealing for whatever reason. There's a difference between that and feeling disgust or contempt for people whose sexual interests differ from one's own.
For example, a straight woman may find the idea of eating pussy thoroughly unappealing, just as the idea of interacting with dick may gross out a gay woman. However, the straight woman's "visceral aversion" when it comes to the idea of performing the aforementioned sex act myself doesn't mean she has a "visceral aversion" to people--male or female--who do enjoy engaging in that sort of activity. That's probably the difference between simple disgust and moral disgust.
Even if she did feel a visceral aversion to lesbians, it doesn't necessarily mean she feels it's OK to talk about them as though they're the punchline of jokes, or subhumans who don't matter. And even if she did feel that it's OK to talk shit about lesbians, it doesn't mean that she feels they should be barred from enjoying legal and social equality.
It's not as though there's a simple either-or when it comes to moral disgust and how one consciously or subconsciously classifies people.
Your friends may be philosophically inclined to want to let people live as they want, and/or they may inhabit niches in which gays are not much on the mind. But a simple look around at the rest of the world--including quite a few of the people on this forum--would indicate that you're probably too generous in your assessment; a lot of men do seem to spend quite a lot of time fretting about homosexuality and railing against it and complaining about having to picture or think about having man on man buttsex, despite the fact that nobody really makes them do so.
I agree with this. Although there's probably some truth to it, especially with some people who have severe and very public negative reactions to homosexuality, I think this is a cliche that pleases the socially liberal because it's thought to piss off "homophobes". People are perfectly capable of feeling disgust for those who are different from them while not fearing there is any similarity at all between them. The anxiety that is the root of a lot of moral disgust is frequently very different from a simple "protesting too much".
Some people who study this stuff distinguish between "homophobia", meaning people who actually feel dread at the idea of having to interact with or think about gays, and "homonegativity", which is a broader term that comprises homophobia.