You mean they;
"devalued heterosexual marriage"
and the world HASN'T stopped on it's axis? Goodness me, who'd a thunk it?
And don't forget my personal favorite bumper sticker slogan battle cry: us godless gays are "defiling the sanctity of marriage".
When I get in to it with homophobes, I like to point out how (here in the U.S.A.):
1) We live in a country where a drunken Britney Spears can have her Vegas marriage annulled, less than 55 hours after tying the knot.
2) Individuals such as Elizabeth Taylor can get married eight times, to seven different men.
3) Our so-called religious leaders like the Rev. Jessie Jackson... our televangelists like Jimmy Swaggart and even our former president such as Thomas Jefferson and Bill Clinton can engage in extramarital affairs and still retain their positions and adoration of their supporters.
Then, I conclude by pointing out how those damned heterosexuals have done a pretty fine job making a mockery of the institution of marriage all by their lonesomes.
Funny how the holy-than-thou types never suggest outlawing divorce, what with it breaking the solemn vow made before god "To death do us part"....