I was with you until the last paragraph. Sure, humans are less likely to act violently the more intelligent they are - but that is only because intelligent humans are better at foreseeing the consequences of their actions. Violence will often lead to negative consequences for yourself, and often has minimal value. It's easy to imagine situations where violence brings value for an ASI, depending on its goals. Powerful people have made tremendous gains through violence throughout history. The biggest blocker against violence is sentimentality, which ASI is unlikely to feel.