Of course gays are fighting hard for marriage, they've never had the benefit of knowing any better.
AZANON, we've debated this on occasion, and honestly I don't think it has anything so much to do with sexual opportunism as it does with the limitations the institution of marriage requires. It's easy to think "well, guys just want to get off with as many women as they can and marriage hinders that for them, therefore it's a selfish sacrifice", and while that's true, there's a lot more to it than just that. If I'm clinically sterile and cannot have children, why should I get married? What benefit is there for me that I can't get remaining single?
I realize there a lot of touchy-feely studies touting the mental, health, financial benefits of marriage, but every one of these presupposes, first a healthy marriage, and second that these same benefits couldn't be enjoyed outside of marriage were marriage not an option to the individual. And still, I wont deny that there aren't some aspects of marriage that are very beneficial, but the studies are biased in favor of being married due to it being a social norm. How many studies are done touting the benefits of remaining single? Far less I'm sure; not because it's less valid, but because it's not seen as a societal norm - and that's the crux of the studies. Maybe the question ought to be, which gender benefits most from marriage? And that's going to universally be women. So in light of that, why wouldn't feminine influence create social contrivances that develop into norms which encourage marriage as being wildly beneficial to both?