Why does the Religious Right try to dictate public policy?

All the news pundits are talking about how Obama is going to lose Evangelical support for 2012. I say good riddance! I still can't figure out why politicians pander to these people. They're so self-righteous and annoying, going around preaching about "morals" and "values", telling people how they should live their lives or go to hell. Their politics are so backwards: Abstinence? Get real. What's wrong with educating teenagers about safe and birth control? Why are religious people so anti- and fun? Creationism taught in schools? I thought we were trying to educate kids about FACTS, not fairy tales.