On one hand, the US has spent several decades, almost a whole century after WW2 building and supporting a rules-based international order where they are the most prestigious and powerful. The very system of international trade and the international laws are set up largely to favour the US, or at the very least, US corporations and their version of capitalism.
On the other, the US has also very specifically said for several decades to almost a century that they do not give a shit about international law and anything of the sort. They'll do what they want and if you don't like it they have no problem bombing you or invading your country.
They've been pretty honest about it all along. They don't really give a shit what the UN thinks. What is the UN going to do about it? Write a sternly worded letter?
If congress cared enough, they have the power to put a stop to it. But they won't. Because they're more interested in profiting off it. Or at least, enough of them are kept in the loop to profit off it that any attempt to stop this sort of actions will fail
The system is basically set up to allow this sort of thing to happen. And as long as it only happens to South American and African countries nobody really cares enough to do anything about it