Christopher Hitchens recently ran an article called "Why Religion Poisions Everything." I didn't bother to read it - the title alone is enough.
I don't know about anything else, but a cursory glance demonstrates how thoroughly religion poisons paintings. Like this one, by a practicing Catholic no less:
Whoops, I meant this one - deadly as all get-out!
Um, sorry, I keep posting the wrong picture...ah! Here we are! Smell the religious poison, folks!
As brutally graphic as the last one was, I felt I needed to make the point.