Because we Americans are fed up with non-Americans and their decades-long epidemic of their vile, hateful, chip-on-shoulder, childish inferiority complex about us and trying to denigrate this country's accomplishments to satisfy their own parasite egos. While using us for every free ride they can. It's been going on so long, it really is the ultimate reason I xenophobically detest non-American filth as much as I do. I've seen other countries' rotten, stinking, reprobate characters.
Oh, and I've done enough travel abroad one promise I can make about the world is that non-American vermin are fatter, stupider and 543094023840 times more xenophobic than we could ever be even if we tried. Ergo, the rest of the world is more full of shit than a goose that's been overfed for foie gras.