I don't think gays, or at least the gays who participate in "Gay Pride" parades and rallies like this on, who dress in costumes designed to shock and disgust people with conservative views (men in assless chaps and wedding dresses, for example), really want "gay marriage." They just want to shock and disgust "the mundanes" and get attention. If they were really intent upon getting the larger society to accept that gays should be allowed to get married just like straights, they'd dress like straights and act like straights and in general try to reassure straights that they really are willing to join society and work with it not against it. That's how everyone else who wanted to be accepted as a normal part of society used to act, and that was how they got accepted.

Marriage is seen as a normalizing act -- an indication that you are willing to give up your carefree single lifestyle in favor of "settling down" and doing your duty. Obviously in these modern times marriages rarely work out that way, but if you don't want to settle down or give up any of your single-life freedoms, then what are you getting married for? One can only conclude that you're getting married in the crass desire for a party, attention, presents, money, benefits, that piece of official paper, and prestige. This is what it looks like at least some gay marriage activists are after -- they have no plans of "settling down" with their partners into some sort of sober, stable life; they just want all the goodies and to be able to shove it in the faces of Christian fundies: "Nyah nyah I got married!" It's all very childish. I imagine many non-flamboyant, non-attention-seeking gay people who sincerely want to be accepted as normal members of society are very frustrated by the counterproductive activities of the in-your-face gay activists.