Race is just a correlation, the causative factor is the culture associated with the race as practitioners of falun gong (who include the Han people) are also targeted.
In America, I have the freedom to brainwash people into following Scientology, in China such cults cannot exist. The line of demarcation is blurry, when does a religion become a cult? How is the fantasmic stories of walking on water or coming back from the dead in christianity make it any different from scientology?
When China sees serfdom as part of the Tibetan culture do they label it backwards and raze the entire belief system or do they leave it alone? https://www.theguardian.com/commentisfree/2009/feb/10/tibet-...