EDIT: I see my post is being downvoted. I know that it may come across as insensitive to immediately leap to the gun control debate, but frankly I'm more angry than upset by this news. How many times does it have to happen? We have a good 48 hours of emotional outpouring and then everyone forgets it ever happened.
We don't know the backstory here, but usually these events are all about someone whose life is spinning out of control for any of a dozen reasons, and either nobody has a clue that anything was wrong or everyone thought that the guy was a timebomb and did nothing.
For example: think about speed bumps. Sure, we could just blame any drivers who crash into pedestrians in parking lots, but by adding speed bumps, we are reinforcing what people already know --- that speeding through parking lots can be dangerous.
Same thing with seatbelts --- you know that annoying chime that won't stop until you've buckled your seatbelt? Why do we need that? Why not simply blame any drivers who crash? Because it reminds people to do what they already know they should be doing. It reinforces safe behavior. It helps to reduce a burden on society --- the negative effects of fatal car accidents.
So I have a hard time whenever I hear someone say 'the problem isn't guns, it's the people who use them', because I think that's only part of the solution. Should people be allowed to purchase firearms "same-day" at gun shows? Should people be allowed to purchase and own as many guns and as much ammo. as they please? Is there something wrong with at least discussing possible reforms to make it more difficult for people to buy guns?
Modern society seems to be good at creating situations where people feel powerless or like lashing out. The offender obviously makes an awful choice, but maybe we should think about how to make things so that society isn't so brutal?
I say that gun control is the "easy" answer because it is a response to a specific event. That doesn't mean that I think that gun control is "bad". I'm just saying that the underlying issue that leads people to do awful things has other negative (but not as horrific) effects too.
As an unrelated illustration, the 14 year old inner city kid walking around with a gun or knife feels miserable and powerless. The weapon makes him feel empowered, but in a negative way -- if he grows up that way, that's going to leave him vulnerable to substance abuse and that mindset will be passed on to his kids and his social circle too.