Keep following that line of thought, don't stop there! Why did those violent behaviors succeed in being selected for? Why didn't pacifism get selected for instead? Why does the government maintain a monopoly on violence, and why is it that the nth-degree consequence for violating societal laws is violence, instead of a monetary fine or a sternly-worded letter? Is there perhaps some kind of game-theoretic equilibrium that causes agents who employ violence -- even as a measure of last resort, after peaceful negotiation -- to succeed in achieving their objectives?
People, corporations, organizations, and nation states who employ violence do so when and because they expect it to work. An AI would need to be very specifically designed not to do that; it wouldn't be the default output of a search for a successful strategy.