You've put your finger on EXACTLY what is going on.
darn straight. It's not the guns. It's always people with long histories of mental illness who BELONG IN SANITARIUMS. There will be a lag time before the media reports this guy was insane. First, they'll find his friends and neighbors who will say he was such a nice guy. They need to do psycho in your town alerts just like they do predator alerts if they aren't going to institutionalize them.
Why aren't we protected from them? Who wants to be murdered ordering fries?