I understand his reasoning and it is sound. But it also can be considered in error in a number of ways. People believe they can do things about car accidents as most Americans think they are good drivers anyway. For that matter most people have some degree of choice about their medical providers. Likewise typical homicides involve someone the victims know. So in that regard you have some control over who you associate with. But the reactions to mass murders are much like the unreasonable fear that grips areas when a serial killer is known to be active. The prospect of strictly anonymous deadly violence is nothing you can prepare yourself for or act to prevent. It turns every public venue you go to shopping, eateries, movies, church, schools into a possible spot where deadly violence could occur. And that naturally scares the hell out of people. Most American citizens do not have a fortress mentality. They want to go out in public and they want those public venues to be safe.