Jonathan Rauch argues that social conservatives should support gay marriage, because marriage is a good thing, and gay marriages would help support the institution of marriage in society.

Sorry, but that doesn't work for me. They used to make short subjects showing animals dressed up as people with voices supplied by voiceover actors. It was cute, but it wasn't real life.
Gay marriage would help gays pretend that their lives are normal, but it just won't make them normal. I'm not opposed to partner benefits and protection of gays from violence which has been ignored by society in the past, but gay sex and gay lifestyles will always be the elephant in the room, and you can't hide it by putting a shade on its head and calling it a lamp.