I didn't vote for Obama. I'm a Christian. If I had, based on my opinon, it wouldn't have been a sin. The man didn't say he was banning God, or anything silly like that. Get real.
And while I didn't vote for him, I know the difference between a political office and, say a candidate for marriage.
I have a new dentist, don't know if he's an athiest, Hindu, etc. While I care at a personal level, I couldn't care less on a professional level since he doesn't hurt. See the difference?