I agree with blastula's post in this thread: "Just because he's Muslim doesn't mean he's not crazy. Some of the recent lone wolf attackers do seem to have mental issues. Violent Islamism may be attractive to someone of a certain bent, just like how some school shooters are attracted to or obsessed with past shooting incidents like Columbine."
I agree as well. In fact, not only does being muslim not make him not crazy, but being muslim makes him a little crazy. At the very least we know he has an imaginary friend.