Earlier quoted context omitted.
It serves another purpose: Deterring potential enemies and giving confidence to allies. For example, the US has contributed to international peace East Asia for generations in part by having underlying muscle available. And today, if the US military tech was removed, I have a hard time imagining that alliances with Japan, S Korea, and others, not to mention Taiwan's freedom, would survive.
Wait, what? Did you miss the bit where they bombed North Korea until they had killed about one fifth of the population, and destroyed basically every form of standing shelter? Or the war in Vietnam? Or the support for South Korean dictators, even as they murdered their own people? If that's a contribution to international peace, I hate to imagine what you'd think was a contribution to regional instability. Even on a…
Overall I’d say it’s probably done more good than harm.