I'm not too sure. The game is based on the Book of Enoch, a Jewish religious work, but the game doesn't really present it self like anything that would be offensive or vulgar to anyone (like God of War or the GTA series). Still, the Jewish community has done of bang up job banning Christmas carols and productions in schools, and removing the Nativity scene from front lawns so it wouldn't be surprising that they viewed this game in the same wary. My guess is that El Shaddai isn't exactly popular with a lot of Wal-Mart's customers, so they might have decided to stop carrying the title in their shelves.
Sorry, but you'll have to look elsewhere.