Je suis le walrus. Goo goo ga joob. Just because a bunch of people carry arms, does not necessarily imply that criminal activity will become less. It means only that the intended target will be able to offer a more effective resistance. Crime is a risk, and crime is business.
Criminal activity is just that, because someone decided that it was.
Crime is evil, if only because it violates the natural law, which says that you may do as you please, as long as you do not harm the life, liberty, or property of another human. And, if your considerations are such that the idea of individual liberty, law, and due process are merely coincidental to your own pecuniary considerations, then no value system is cardinal to your thinking. In any case, no matter. We have witnessed the slaughter of innocents by any camp, whether the government, or private, contracted henchmen. We aren't there yet.