Dudes, the murderers have not been arrested yet. Nobody knows if they're muslims, christians, jews, buddhists, atheists or anything else. If they're atheists, then atheism must be eradicated? And if somebody kills a baby while screaming "666 the number of the beast" automatically proves that this guy is indeed a metalhead? Does it prove that heavy metal is the music of terrorism and must be eradicated?
The only thing that's sure so far is that the guys that have comitted this massacre are totally mentally insane and must be arrested and punished by law.
Edit: I'm not promoting any religion at all. I'm an atheist. But now it's a police investigation and I think we have to be pragmatic and not fall into interpretation, etc.