Is your only exposure to the world of metal through radio, or through angsty adolescents?
There’s many millions of people all around the world that would disagree you vehemently. There’s a reason the album they put out in 2010 reached 3rd on US Billboard.
If you knew the effects it has on the individual and society, you might choose something else. Check out this book:
http://books.google.com/books/about/The_Secret_Power_of_Music.html?id=HcZ6QgAACAAJ