US hegemony exists to maintain the global order, prevent unnecessary wars, and advance democracy, so.
To be clear, before you throw up your hands and walk away, I'm not saying everything we do is great! The US did all kinds of terrible stuff! It's still doing bad stuff! But I'm also saying that ultimately, the goal of the American military and intelligence forces is to promote the welfare of America, and the easiest way to do that is by just being mostly friendly to other countries and avoiding making them angry. Diplomacy is very efficient!
If you want to see what a bad actor looks like, you can actually do that. It's Russia! They've deployed their military and intelligence forces aggressively and scared and hurt other countries, and now they're being heavily sanctioned, their economy is cratering, and they're diplomatically isolated. That is what happens when everybody hates you because you're fucking with them too much! But that isn't happening with America. Even our enemies want to trade with us!
America is a big and very powerful country. But the world is full of power blocs that exist to help provide counterweights to powerful countries. If we were constantly stomping on everybody else, people would organize sanctions against us. If you think that isn't possible, just wait and see what happens after four years of Trump.
The fact that people instead look to us for military and economic support and want to get along with us, allow Americans to travel to their countries and do business there, etc., should be taken as pretty strong evidence that American hegemony is...mostly okay with everybody? Not literally everybody. Obviously there are some places we need to keep working on, in some cases because they think we're bad actors, in some cases because they're bad actors. But I think people really don't seem to grasp what would happen if America really was an international pariah. Nor do they understand what the Pax Americana actually prevented, or why it was put in place. I'll give you a hint: because there were two huge world wars, a massive genocide, and also everybody has nuclear weapons now.
Keeping the peace in Europe is not a minor accomplishment. It's historically uncommon, very challenging, and quite important to the general welfare most everybody in this thread enjoys. You can thank American hegemony for that! Or you can just wait and see what happens without it. I warn you, it's going to be a rerun.