The evolution of hate
When I came out in the early 1980s, one of the standard excuses that the bigots used to justify their homophobia was that LGB people didn't care about love; all we wanted to do was fuck and thus our "avoidance" of committed relationships proved that we didn't deserve equal treatment under the law. Two decades on, we've proved pretty eloquently that this is not the case and that we'll fight enthusiastically for the chance to get involved in committed relationships, whether or not the government sanctions them.
"Okay", say the homophobes, "that first argument didn't work, so we'll just make something up and see if we can sell it!" So now the argument for not providing equal treatment under the law has changed subtly to "it's traditional to discriminate against queers, so your rights as human beings are trumped by our rights to preserve the discrimination we're used to." This is the same sort of argument that I hear 4-year-olds make about anything (usually at the top of their lungs): I DON'T LIKE IT! YOU CAN'T DO THAT BECAUSE I DON'T LIKE IT! YOU'RE BEING MEAN TO ME!
I expect that when this latest round of evil from the hate amendment crowd (these people claim to be Christians, but I've never seen a lick of Christian charity or compassion from any of them) is finally kicked into the grave it richly deserves (either when the Oregon hate amendment is defeated at the polls, by the Supreme Court, or when Canada annexes Oregon after the United States disintegrates into civil war) that their next approach will be "Look, not very many gay people are married. They don't want committed relationships and should be discriminated against!" as if the past 25 years had never happened.