POLL: Why are people trying to eliminate gay marriage and equal rights based on moral beliefs?

Isnt there separation between church and state? Why do people constantly say that gay marriage is against the law of god and is immoral and uses that as their argument to oppose legislation for gay marriage when there is separation of church and state? Also there are 7.5 billion people in the world.. Not everyone has the same belief as you.. Im just asking why? Like I want reasons because I want to understand.