A lot of freedom of association rights were eroded during the snivel rights movement. Techincally the Constitution should guarantee people's rights to do business with and associate with whoever they want to, and nobody else, but the Constitution has been crushed under foot. Personally I wouldn't want to participate in any way in a gay or lesbian ceremony either, and I'd feel almost as strongly (though not quite as much) about a ceremony involving miscegenation. I wouldn't want to have anything to do with that either based on my personal feelings about such pairings. I think freedom is being stepped all over when the government forces you to participate in rituals that personally disgust you or that are outright immoral.