In my book anyone who would commit a mass murder is "crazy". I did not call the shooter a schizophrenic, or a psychopath, did I? "Crazy" is a colloquial term, not a medical one. That said, anyone who would kill random innocent people qualifies as a sociopath at the very least.
Most people who commit mass murders are not "crazy" - they don't have psychosis, they know what they're doing, they plan the attack.