As in being an ally? Obviously I support it. It's just plain dumb not to. Face it, they're the majority and there's only ever going to be change because of what they believe and want.
I hate it when you have people who pretend to be "part of" the LGBT community, just because they think it makes them edgy and "different".
But if a straight person feels strongly about it (maybe a loved-one is a victim of homophobia), then they should express their support! After all, we all feel strongly about something that doesn't directly affect us personally. How many of you (males) have a strong opinion about abortion? Yet that will never directly affect you personally.
I think it's wonderful when straight people support the gay community! Ask someone else said, the more the merrier !