My point is that Wends are not the same as Poles, and yet the differences between Han peoples are greater than the differences between Swedes and Sicilians. How can you claim China to be "largely mono-ethnic" when you don't look or talk like someone from Shanxi?
Chinese-Americans are descended from Taishan people and should not be confused with people from Shandong. Height requirements for the San Francisco police and fire departments (previously set at five feet eight inches) were abolished because the Chinese-Americans sued claiming it was racist against them: https://en.wikipedia.org/wiki/Fred_H._Lau