I'm not saying there's no such thing as people who do what you describe. There are definitely examples, like Mayhem, of people whose act is their real life. I'm just pointing out that for some reason some people have this automatic assumption that song lyrics are a literal description of the singer's personality or beliefs and for whatever reason these same people usually don't make the same assumption about directors or authors.
I guess my point is that an artist is separate from their work and it's important to keep in mind that the stage persona of some gangsta rapper or metal singer is most likely just a character that they are playing. I mean look at Ice Cube. On the one hand he wrote a bunch of violent lyrics for NWA but on the other hand he wrote, produced and starred in the movie Friday which has a pretty strong anti-violence message. I think there's obviously more to the guy than some violent NWA lyrics.
Lyrics don't have to be literal. Most aren't. I mean, autobiography isn't the only way to express yourself. Just think of all the great books and movies out there that are fictional stories. The people who created them were still able to be passionate about their creation without actually having or even desiring the experiences of the characters in their creation.
