This is a placeholder - it may be worth coming back to it. At the very least, you can see a blatant attempt by the Catholic Church to get its theological view of marriage accepted in the political process. Do its arguments strike you as secular ones? Perhaps some do strike you as facially secular - okay, do these "secular" arguments, strike you as at all strong? Do the factual claims relied on have any serious scientific backing? What sorts of assumptions are being made but not stated?
I'll leave all this for now as an exercise for readers. It at least shows the kinds of highly-organised efforts we are up against when we complain about religious interference in politics.