The post is titled the Chinese Muslims, not the Muslims of China. One may make a semantic distinction here in that the latter connotes the residence of a Muslim community within Chinese society, while the former indicates members of Chinese society who happen to be Muslim. Such black and white dichotomies are naturally artificial, but to a large extent the Uyghurs of Xinjiang fall into the category of a group of Muslims (of Turkish language) who happen to fall within the boundaries of the modern Chinese state (thanks to that inheritance of the Chinese state of the full expanse of the Manchu Empire of the 18th century). On the other hand, the Hui people are arguably more a Chinese people who happen to be Muslim.
For more on the topic, please see my blog post at the Islam in China website. It was submitted a while back, but it only went up recently.