Indeed. This is how we are forced to respond to such senseless acts of violence: with violence. All reasonable steps must be taken to identify and stop those who would kill, but disarming ourselves in an attempt to get them to do the same is not an option in today's America. Maybe when we have evolved into better people, but not as thing currently stand.
I recently read an article on the process to become a gun owner in Iceland, where they know practically zero gun crime. It involved lots of training, a lengthy interview by your doctor and law enforcement, testing and it took about 18 months for a long gun. Getting a handgun took several years. But most impressive was the attitude of every person they interviewed and their understanding of the responsibility of holding the power to potentially take a life in their hands. They didn't even seem to think of guns as a tool for self-defense because there was no need in their society for such. The idea of being able to walk into a store and buy a gun in an hour, even with a background check, seems idiotic to them, especially if you had no training and didn't know how to use it. Most of their law enforcement is unarmed, and those that are carry their guns secured until a supervisor gave permission for them to be released. Icelanders only see guns as tools for hunting and target shooting.
I wish such was the case here in the U.S. Of course, Iceland has far less income disparity than we do. And, apparently, a much higher respect for the lives of their fellow countrymen. What's wrong with us?