>It is not that we have an unusual proclivity for aggressive violence. On the contrary, most other species are far more aggressive than humans. Chimpanzees, for example, are over 150 times more likely to initiate violence against each other than we are. Rather, our species is characterized by low rates of aggression and conflict but extremely high lethality rates when conflict does arise.

I would argue that increased legality IS increased aggression. A person can whack me with a stick or they can shoot me in the head. One is a more aggressive act than the other.