I find the whole anti-gay marriage argument bizarre. If you don't like gay-marriage, don't have one.
I don't understand straight men dressing in ladies underwear, for example, so I wouldn't do it myself - but why should it bother me if someone else does that in the privacy of their own home?
It's fine to not like things yourself, but it becomes homophobia when you try and impose your view of the world onto other people, and prevent *them* doing things that *you* dislike.