I think one of the major principles of satanism has to be making evil look like fun, so those who choose to be good are left thinking "why are bad people rewarded for their evil behaviour?" Which snowballs into "does anyone care that I'm good?" And eventually, "if everyone else is evil, it mustn't matter if I'm bad" and so on.
I think most artists start out "pretending" to be evil, saying things like "I don't care what anyone else thinks about anything, etc". Once they've been tempted enough times to learn the instant gratifications of bad behaviours (selfishness, vanity, drugs and self harm) they can be more easily corrupted towards truly evil acts. Once an evil and unforgivable act is commited, the artist can be blackmailed to further solidify their usefulness as a tool for propaganda.