American culture is becoming more secular -- so why is there so much religious imagery in our entertainment lately?

In surveys, the number of Americans who classify themselves as practicing Christians or Jews is on the wane. So why is the use of Judaeo-Christian tropes in American mass entertainment on the rise? Lucifer, Sleepy Hollow, The Exorcist etc.

“These intellects may not believe in God, but they fear us just the same.” —Erykah Badu

“tropes” is probably not the right word, but I think my point is clear enough.