You can often see the same sort of violence with sports fans. Simply google "fan assaulted during game", and you'll get any number of results about fans from competing sports clubs becoming violent with each other. Statism isn't unique in this respect.
It's an unfortunate result of the combination of our inborn need to identify with a social/tribal group, and the growth of the size of nations in the last few thousand years. We're not neurologically equipped to instinctively grapple with the implications of identity groups numbering in the hundreds of millions, and this prevents us from truly appreciating the effects of our "group's" actions. What would be a small squabble between tribes over, say, hunting grounds becomes much more serious when you involve millions of people and tanks and bombers rolling into towns that probably have no connection to the conflict itself except for the fact that they're members of the 'group' with which the conflict is taking place.
I think that the next step for our species will be to, not overcome our social tendencies, but rather, for them to become more nuanced and sophisticated, in order to grapple with the complexity of global interrelationship that is the norm in the modern world.
The need to identify with a social/tribal group is not inborn, it is forced onto children at school. If it was inborn then everyone would display this need to identify and empirical evidence tells us that this is not the case. Those of us who understand this need is both illogical and harmful fall into two categories, those who were not convinced by the propaganda from the start and those who've overcome the propaganda through education. As I changed schools 19 times I'm fortunate that I mostly fall into the former category although there may be some shades of grey in the middle.