[metalman]

Japan is still a mono culture, living on islands, China is anything but, though they have exactly one rule for everybody, which is "dont mess with the brand", ie : you can have a sub culture as long as nobody else notices. And WOW do they have a bunch of subcultures nobody notices, because they dont want any attention, that bieng realy bad mojo and so survial is to not exist in any overt or competitive way.

[decafninja]

Most of the people of those subcultures are phenotypically not too different looking than the dominant Han ethnicity though.

Like you said, the fact that China is authoritarian is a big factor in all of this.

The "melting pot" West does have numerous phenotypically similar caucasian subcultures, but also many non-caucasian ones that do not look phenotypically alike at all.