Just kidding. Of course they are bigots! They are bigots par excellence.
But they hate to have to admit this and they hate to be told so. They say that their arguments against same-sex “marriage” — they always put the word in scare quotes — derive from the natural law.
As if saying it’s from the natural law ends the discussion. First, no, marriage is social not natural. Second, natural law is itself philosophical not natural.
It does no good to polish up bigotry by calling it natural law. Rather, if the metaphysics behind your precious conception of natural law lead you to bigoted positions, consider that it’s the metaphysics that are in error. You need a different metaphysics.