In your examples the murdering was done in a systemic fashion, i.e., driven by the state. It is not relevant for the discussion here.

Not necessarily, e.g. the Normans had a well-deserved reputation of being extraordinarily violent on their own. Even Norman bishops were known to travel armed and get into fights. (And the state back then was far too weak to prevent such behavior even if it wanted to.)

Also, gangs can be seen as proto-states, and a lot of today's criminal violence is gang-related. There isn't really that much difference between, say, drug cartels and the kind of violent packs of future nobility that raided and terrorized Early Middle Age villages in the post-Roman world.

I'm very sorry, but I have difficulties relating this post to the earlier discussion. I'm sure you are factually correct, but the examples start to be so far removed (and in some sense not terribly relevant even as edge cases) from the earlier context that I simply can't add anything without sounding terribly rude.