Just for the record, I don't think John was into Satanism, at least not at the end.

From Bring on the Lucie (Freda People):

We understand your paranoia But we don't want to play your game You think you're cool and know what you are doing 666 is your name So while you're jerking off each other You better bear this thought in mind Your time is up you better know it But maybe you don't read the signs

Well you were caught with your hands in the kill And you still got to swallow your pill As you slip and you slide down the hill On the blood of the people you killed

Stop the killing now Do it do it do it now

Also, Bowie hired an exorcist to clear the demons out of his house, (and presumably, his life) And Leonard Cohen lived in a monastery for years to escape his demons. The occult targets influential people, but not all of them are into the truly horrible shit. I imagine alot of them get into it as a means to be avant-garde, and end up distancing themselves once they realize what's actually going on.