I finally found the source of this strange Chinese-Turkish internet skirmish.
I'm German here. I train myself horse riding in China and know not only Uyghurs but also Kazakh, Kirghis and Turkmen as friends. Those central Asian ethnicity groups all identify themselves as citizens of their sovereign states. I have not met a single Uyghur who does not consider himself or herself Chinese.
It is actually quite interesting for Turkey: Germany has very large Turkish immigration population, and Turkish government has been very long accused by German authority of promoting Turkish nationalism in Germany, e. g. "funding religious groups, spreading anti-democracy disinformation in Germany" and so.
I for long thought it is some false accusation made from German political circle individuals. But seeing how some Turkish community always encourage the minorities living in one countries to "leave" that country: This is very dangerous, and now I believe the accusations made by German authority is likely true.
This is very inappropriate, and it crosses the line by both European and Chinese standards.