In his September 20th column, Dan Savage provids a concise explanation for why "Bible thumpers" and other conservatives are often sexually intolerant: they shift the focus away from their own "improprieties."
Your friend, like a lot of Bible thumpers, needs to feel morally superior to someone. And looking down his nose at you in your little-girl dresses and me in my big fag relationship allows him to feel morally superior at absolutely no cost to himself. He doesn't have to refrain from fucking hookers or cheating on his parade of spouses to get right with his make-believe God. He need only refrain from doing things he has no desire do to--sucking dick, dancing around dresses--in order to go to his wholly imaginary God's entirely fictitious heaven.