I live in one of the exceptions to that, and still have zero concern that someone's going to shoot up my workplace. Again, civilization works because the vast majority of people are utterly repulsed by the idea of harming another person.

Most of the hypotheticals that people come up with are things that could pretty trivially done by a mad scientist today. But that doesn't happen, because this isn't a comic book, there is nobody hell-bent on turning everyone into dinosaurs.