Yeah, Uri had a bad life that was not his fault, sure. You still don't want a whimpering indecisive simp in a position of power. Nothing seen in the story so far indicates anything about him that would make him a good ruler and leader. Given that this is a dumb manga story, it will of course...
The guy with the sword deliberately sets up a convenient straw man for Thorfinn to knock down. Yes, of course rash and irritable people with weapons are a danger. But the balance argument is still valid, once there are weapons in the world at all, in the long run you will be on the losing end if...