[nlfwhulsdhouv]

No it's not, and the US is far from the only country that has a diversity of culture. The Canadian maritime provinces are extremely different from Nunuvut or downtown Vancouver. Paris is significantly difference than Nice. Shanghai is significantly different than Xinjiang province.

This is yet another annoying expression of American exceptionalism. Of course, it only ever comes up when someone says, "Maybe we should stop people dying because they can't afford healthcare."

The US is probably one of the most culturally uniform countries of any significant size I can think of honestly.