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.