Unfortunately for international law, the United States never follows it ever for anything.
This is not an isolated or exceptional case of the US electing to ignore international mandates in order to respect its own constitution, or the will of its own people. Or even just because the US government is full of dick heads who know they don't have to follow rules.
Yet, the US continues to get away with it.
Probably because everyone knows there's nothing they can do about it, and that it isn't ever going to change.
And probably because a cordial relationship with the United States is more beneficial to the international community than embargo or sanctions.
Some would say that international lawmakers are giving the US all the power, but in my opinion, the US isn't given power by anyone. The US exercises the power it already has, and everyone just knows that they will have to deal with it.
This is a question beyond the issue of what's right and what's wrong. It deals with ideas that are less complicated, ultimately, than whether or not a country should respect its constitution (a constitution the majority of its citizens support). This question is more primal:
What do you think you're
gonna do about it?