@snood,
Consider the possibility that the root of your instinctive reaction comes from simple attraction (or un-attraction) and not homophobia.
If you imagine an incredibly unattractive hetero couple with an unattractive female kissing, do you have a similar feeling of "distaste" as seeing two men making out?
Conversely, if you imagine a more attractive couple, especially the female, then the disgust is reduced, except that you may still be uncomfortable with Public Displays of Affection.
I think these types of "distaste" are rooted primarily in simple attraction, and secondarily in the tendency of people to be uncomfortable with virtually anything which they are not accustomed to seeing.
In other words, the reason seeing men kissing is distasteful is simply because you're not attracted to them. And because you're heterosexual, all men essentially fall into the same category as "ugly women".