Violence is baked into nature. Packs of animals will defend each other in a fight. However, some animals in a pack will kill off weaker members of the same pack just for breeding rights. Nature is brutal and it’s the most efficient killers that may win out. (That isn’t always true, of course.)

The article does try and make a connection with violence and the types of weapons used, though. (Humans had bows and neanderthals had spears.)

My point is that violence was likely part of the problem, but not the entire one.