Domestication & Violence
While warfare has been a constant in human affairs, a countercurrent has been the domestication of humans. (In modern bureaucratic parlance, domestication is called institutionalization.) Much as domesticated animals are bred for passivity, the innate aggressiveness of male human stock has been tempered by killing off some of the most violently inclined. Wars helped somewhat in that regard.
More generally, sustained violence is frowned upon in most cultures, and in modern times has been claimed as a monopoly of the state. Suppression and sublimation of aggression are typically encouraged by ruling elites, who fear that violence unchecked may come to be turned against them.
Thus, strong cultural norms subdue innate male propensity to violence. Nonetheless, as a glance at the daily news on any day reveals, civility remains a limited commodity. Violence, whether physical or economic, is a fact of everyday human experience.