I think this specific USA team brought it on themselves. Paul Skenes set the tone before game 1 with "We're America, we've got to assert our dominance over everybody else. That's what we do" and it was basically constant douchebaggery from there. Combine that with having the most talented roster in the tournament and people were going to root against them, for obvious reasons.
Its like if the Yankees at their peak also acted like the world's biggest *******s.