You slightly misread what I wrote, I was not comparing Han Chinese to all of Western civilization. Inadvertently, kind of proving my point. You took the entire concept of "western civilization" to make an analogue. That's not a great comparison, wouldn't you agree? Actually, I would simplify it to something like if an actual unified British culture existed, rather than separate Scottish, Welsh, English, Irish/Northern Irish etc. identities.
Minorities in China comply with the western idea of ethnic groups in name only. As you mentioned, the communists took the Soviet methodology (basically land and language), applied it broadly (and sometimes arbitrarily). However, practically speaking, most of these people live a life undistinguished from Han Chinese. I am not familiar with census results, but generally speaking, declaring yourself part of a minority group is to usually trying to reap affirmative-action type benefits (access to employment, university entrance qualifications, number of children, etc.). It is easy to go back and forth since Han identity is not tied to religion, blood, or even spoken language. For example, former drug kingpin Khun Sa fancied himself both a liberator of Shan people in Burma, but also patronized Chinese schools and entertained himself with Taiwan TV and music.
I try to find recent Marxist writings from China to study how Chinese style Marxism evolves. The best source i found is this: