My pet theory is that puritanism is an inherited trait (not sure if genetic or cultural). america has a lot of it due to its history. The descendants of the puritans have given up all sense of religion, which actually, for them, was a net benefit, since having an external, well-organized religion actually would pull them back from their religious zealotry (by discouraging pride for example).

Now, completely unmoored from their actually somewhat stabilizing traditions, these children -- already predisposed to puritanism, zealotry, etc -- have taken up new belief structures, except now there's nothing to bring them back to reality.