Americans are not uniquely stupid.
Successful types surround themselves with other hard chargers. As a result, we start losing our feel for the "average" human. Sure, this report is surprising and disappointing. But that's because we've let our perception of "average human" drift. Go to Walmart and spend an hour on a bench watching people interact with each other. Watch their body language, observe how they are dressed, listen to what they say, not just what they are talking about, but their word choices and their diction.
Then come back here and you won't be surprised at all. Think of your Walmart time as a "recalibration" of your perception of the average human. Then hang out with someone that makes you laugh and have a few beers with him/her. That will make you feel better.
Books @ Amazon "If only he had used his genius for niceness, instead of Evil." M. Smart