So the dragons that go insane, if the Rato tribe doesn't stop them, would go on unstoppable rampages. Tsuta tribe knows the harm they can do and thus hide themselves away to contain their strength. So isn't Rato tribe doing them a favor by minimizing the harm Tsuta does to the world by taking out the insane dragons and allow Tsuta tribe to continue living in secrecy? Or maybe the Tsuta tribe's issue with Rato is the selling dragon body parts instead of sending them back to the mountain to be buried or that these Tsuta tribe members disagree with the seclusion policy.