It makes him feel different and interesting. If you don't get his lyrics or you think his comments can be slightly cruel at times, just deal with it. It's part of his act. You probably do understand him all too well, and that's what bugs him. You don't always have to be a musician to understand one.
Many musicians also go down the path of indifference.
Sometimes it's a direct result of taking anti-depression meds, but on the whole it's just who they are. It's amazing how musicians seem to pour out their souls in their music, but can't handle an emotional conversation with their girlfriends. On the other side of the coin, your boyfriend might end up being a drama queen. This means he yells a lot about annoying band members or freaks out when the sound system is screwy at his concert. Beware of this type.