Emotional knee jerk responses are plenty after such tragedies. People jump to conclusions with little to no evidence. People think that since it was a crime committed with a gun that the response is to disarm all of the people in the United States (forgetting the fact criminals who murder people will still have guns). Of course, you never see anyone advocating that cars be outlawed when someone decides to kill someone with one.
Another favorite target of well-meaning parents and scapegoating politicians is violent video games. For some reason people feel that a video games that simulates violence must automatically lead to violence. As if somehow clicking a mouse to fire pixelated bullets at fictional zombies will somehow encourage a child to grab a gun and start shooting teachers and little kids. It takes a very disturbed individual to not be able to see the difference between a mouse click and pixels, and taking the lives of twenty people and shooting themselves in the head.