It is utterly irrelevant what any individual religion, including Christianity, has to say about homosexuality, from a public policy standpoint. This nation was founded on Enlightenment ideals, so I think its important to show the practical harm of homosexuality both to the individuals practicing it and to the politity at large. Now, the consensus against homosexuality by the world's religions. including Christianity, may come into play, as does the fundamental status of secular radicalism as a religion in its own right, with fundamentalists adhering to it that make Christian fundamentalists look like lukewarm Episcopalians.