I don't see any demanding anywhere and the only place you will see that is in traditionally democratic strongeholds.
You got to run the candidate that can pull 51% of the vote. Backing a 20%'er may be philosophically satisfying, but you still end up with that big "L" on your forehead on election day while the socialists take home all the hardware. Also, is it possible in your book for athiests to be conservative?
Nope, but then practically anything is "possible". I certainly would never ever vote for an athiest.