RE blanket statements:
I do think it's more accurate to specify a country, in general, but non-Americans make blanket statements about America all the time. "X is popular in America," "Americans hate Y," etc, when what they really mean is "People in New York City, LA, and Chicago like X," or " Americans in small towns in the northeast of America hate Y." It's a huge country, and while we may not have the history that Europe has (though, I would say my family carried some of that history with them when immigrating from Lithuania) , we certainly have a wide variety of different cultures. Sometimes, extreme specificity is important, and sometimes you get the idea and let it go because it's unreasonable to expect people across the world to realize that even though Chicago is in Illinois, it's like a whole other world once you get a couple hours outside of the city.