He was a sometimes homeless guy, addicted to marijuana and alcohol, exactly like Anthony Hammond, arrested for a similar attack in California. These are not  political nuts or terrorists, they are sick people that should have had treatment years ago. Both have arrest records going back to their youth, too. And, neither was a "racist". Hammond had a black girlfriend and bellowed racist remarks. The problem is a society that does not bother to help criminals before these tragedies happen. Treatment, education, jobs.