Here's my take on this. Don't tell someone that they're wrong for thinking something is wrong, otherwise you're just as bad as you say they are. If a person is morally against gay marriages then it's just plain ignorant to expect them to sit by and not care what other people do. I'm morally against stealing and killing, so if I see those in progress or someone who does those things, I will do what I can to effect the situation in the way I see morally fit. Likewise, if I think same sex marriages are morally wrong, I have an obligation to my beliefs (religious or non) to stand up for them. Of course, if they're not politically correct, liberal beliefs, apparently people don't have the right to stand up for them.
I think it all comes down to wanting to cheer for the underdog to be perfectly honest. Gay pride parades occur and no one makes a big deal out of it, but if a bunch of Christians or any other religion that is against homosexuality decided to have a parade expressing their belief that homosexuality is a sin, it's a terrible thing and they're terrible people. That's pretty hypocritical if you ask me.
You say to people who are against gay marriages that just because they think something is so doesn't make it so, well look in the mirror. Last time I checked none of us was Supreme Ruler of the Human Race (TM) and therefore your opinion of the rightness of gay marriages is no more definitely right or wrong than sixates, or BoCo's, or suviko's, or anyones.
If you support gay marriages, great. Do what you can to support them then.
If you're against gay marriages, that's fine too! Do what you can to prevent them.
And neither group has the right to complain about the other being pompous because that is the nature of truly believing in something. If you're not pompous about something you hold true, then you have no right to call it a belief of yours.
My opinion on the matter has been left out. I'll vote for politicians who suport it and that's all that matters. Whether people who disagree with me know my opinion doesn't matter to me because it does nothing to promote the result which I would like to see.
EDIT: heh. Spec and I started our posts the same way