Pre-agricultural societies are generally much more brutal because you need a lot of territory to feed relatively few people. Agriculturalists can conquer other

Pre-agricultural societies are generally much more brutal because you need a lot of territory to feed relatively few people. Agriculturalists can conquer other people and make them work for them in a way that doesn't scale for hunters-gatherers. The consequence is that the combatant/noncombatant distinction is much more blurry, and genocide is often an explicit goal of the war.