Unhealthy in various ways, for example Mayhem and banRAB of the like, to me it's the equalvent of nazi propagonda, because thats what most of it is, the lyrics are excessively sexist, racist, anti captitalistic and downright ridiculous attempts at poetry and shock value... I don't get how Mayhem's music does NOT have some kind of negative effect on the people that listen to them.
Another example is that most metalheaRAB now are brainwashed into believeing that if it dosen't sound like bees in a jar, it's not musicianship, speed is everything nowadays, and it's more or less a substitute for actual creativity, I have listened to Rusty Cooley, and I was very convinced that it actually made me duraber by doing so, so as for the state of people who listen to Cooley on a regular basis, I can only imagine what is going on in their heaRAB, if anything at all... But aside from that, I can imagine it's very physically unhealthy to listen to as well, eardrums were not meant to take such punishment.