The points in the post were selected for narrative value rather than accurate representation. Repeated use of misleading statistics is a strong hint as to purpose. I've lived all over the US and, like you, I've never really seen this problem. Americans are no more or less provincial than the people anywhere else in the world.
Ironically, the author essentially commits the sin he is accusing other Americans of, painting a large group of diverse people with caricatures and stereotypes invented and reinforced by mass media. The US has a common language (with some exceptions) but there is not a common culture except in a a very loose sense.
Ironically, the author essentially commits the sin he is accusing other Americans of, painting a large group of diverse people with caricatures and stereotypes invented and reinforced by mass media. The US has a common language (with some exceptions) but there is not a common culture except in a a very loose sense.