Ay, that's not exactly relevant with violence though. See the concept of fight fire with fire is fight a uncontrolled fire with a controlled fire. So if we adapt this to violence, we fight uncontrolled violence with controlled violence. This won't work though, because there will be a point where the controlled violence would get out of control, I mean, who would be there to control the violence? The people who are there, would probably control the violence, WITH VIOLENCE, and we get more violence, which gets out of control and that's controlled by more out of control violence and we get entire anarchy due to the simple fact that all humanity retains primitive instincts of violence and violence cannot be controlled.