I'm aware of what the US government has been up to, more or less. But it was also doing good things at the same time. There have been plenty of regimes in the post-WW2 era that are just evil. Take the Myanmar junta. They have destroyed civilian rule, carried out a genocide against the Rohingya, and generally oppressed the people.

Much of the US's large record has to do as much with it being a superpower. The people at the helm could do more good or more evil. Contrast that with a country like Iran where the people are brutally oppressed and they routinely fund regional terrorist groups. Iran does less terrible stuff overall, but that's more because they have so much less power. Well, that and a lack of Henry Kissinger, because screw Henry Kissinger.

It's not that the US government hasn't committed terrible crimes, it's just that you're (perhaps unintentionally) giving yourself in to bias. You aren't really considering the true amount of evil done by more despotic and wretched regimes like the ones in China and Russia.