Why are so many heavy metal stars becoming Christian?

I am wondering if because they focus on the dark side of Christian theology for so long like Satan, demons etc.. that when they choose to become positve people this only seems natural. For examples of who has become Christian there is Dave Mustaine and Dave Ellefson from Megadeth (the best band ever), Nicko McBrain from Iron Maiden, the Spitz brothers (formerly Jewish) from Anthrax, Head from Korn, Ralph Santolla of Iced Earth and Deicide, Alice Cooper, and many others. Its kind of a big movement that is confusing many anti-Christian metal friends of mine. What do you think the reason for the switch is?