It's easy to assume that opposition to gay marriage is a simple reflection of hatred or bigotry or self-loathing, but I think to make such broad assumptions is almost as bad as what the traditionalists are guilty of. Marriage is deeply spiritual to a lot of people. There's something reverent and meaningful about "the way it has been done" for hundreds if not thousands of years. I understand the urge to respect that.
It's difficult to respect that when the reason why it's been that way for all those years has been because of bigotry and the marginalization of the gay community.