Seconding this request. I would say the basic argument is similar to arguments against theft as a generalized policy eg it disincentivizes creation and hard work. Generalized violence disincentivizes civilization if you look at civilization as a framework for the interaction of strangers in large groups or individually but interchangeably. Basically, a culture of violence devolves to groups of people that can only trust very small numbers of other people on the level of family or tribe. The idea that you can venture into town to purchase anything you want and not have to worry about being murdered by a stranger is extremely important, in my view.