While I see him claiming that permitting gay marriage is one more step along this path, I don't see him providing any argument that such unions are themselves bad or any worse than the other breakdowns of traditional marriage (such as interracial marriage, multiple divorces, prenuptial agreements, and so forth).
He does not compare gay marriage with other traditional marriages.
When her cardiologist husband (Martin Donovan) leaves her, Judith Nelson (Holly Hunter) goes out into the world, her pain making her receptive to everything and everyone--from the elevator man (Danny DeVito) who returns her friendship with uninvited amorousness to the torch singer (Queen Latifah) who takes her to after-hours clubs, where she dances ecstatically with young women.