It is incredibly difficult to convince a greedy bastard to support peace. The natural order, for millennia, has been that when a greedy bastard meets a peace-loving activist, the greedy bastard takes the peacenik's stuff and then kills them. That is why we continue to have greedy bastards after millennia, and many of the original peaceful hunter-gatherer tribes have been killed off.
Capitalism's greatest success is as a sociopath-containment vessel. Historically, people who desire world domination achieve it by killing everybody else. Capitalism has managed to convince them that the path to world domination is making stuff and providing services for everybody else. This is a huge change in incentives.