Actually, yes, a lot of it IS semantics Buzzard.
I guess you don't know much about our constitution (you are from Canada right?), but if we just permitted "marriage" to homosexuals, then under equal protection, the 14th Amendment, we would have to allow ANYBODY to get married. It may sound like small cookies, and something we could easily stop, but it's still very real.
There is also a lot of principal involved in the matter. The majority of people in the country do NOT condone homosexuality no matter how much you try to argue that it is wrong or bigoted. As long as people are given the chance to vote on the issue, it will be shot-down. It also don't matter how much you try to argue that people are born gay, nobody really cares to hear it because there is no DEFINITIVE evidence that proves it. When the day comes that there is, it will still be probably 50 to 100 years before it's truly accepted among mainstream society, and even then they will still be ridiculed and a VAST minority.
I personally could care less if two guys or two girls want to get "married", but I also don't think we should have to change our personal views in order to suit them. As long as it's put before a vote, I will vote against it because I don't see it as right. Furthermore, when it comes to "benefits" of marriage, I don't really see any unless you have children, at least from a monetary/tax aspect. I don't know any gay couples who can have children outside of a lab, so I think it's easy to see where even some liberal minded people see a difference between hetero marriage and gay marriage.