About the same time nmh and a significant portion of the right realize it I guess.
The left doesn't really care about homosexuals any more than they care about blacks, or any other "special interest" group. The left wants to destroy America's Judeo-Christian culture and marriage is a big part of that. In the 60's and 70's the left through the "sexual revolution" tried to destroy the institution of marriage, but they failed. Now, they want to push homosexual marriage on us; however, it's not about "equal rights" for homosexuals, it's about devaluing the meaning of marriage for everyone else.
So never, right?