Another insight from Steven Pinkers' "The Better Angels of Our Nature," which is about violence and why we're seeing less of it:
"The world has far too much morality. If you added up all the homicides committed in pursuit of self-help justice, the casualties of religious and revolutionary wars, the people executed for victimless crimes and misdemeanors, and the targets of ideological genocides, they would surely outnumber the fatalities from amoral predation and conquest. The human moral sense can excuse any atrocity in the minds of those who commit them, and it furnishes them with motives for acts
of violence that bring them no tangible benefit."