Isn't it pretty well established that farming led to an increase in violence?
Not that I'm aware of. My understanding is that agricultural societies were less violent. As I understand it, when humans are in hunter-gathering societies, we are more territorial and less accepting of those outside of our tribe. (On the order of 50 people.) I'd like to know if that understanding is wrong.
What I do know is that we have gotten much less violent over time. The 20th century, even with all of its wars, was still much less violent than all previous centuries.