For China internal affairs, I do not think China really give a fuss about what other countries think. Basically, China either ignores that or simply tells you to mind your own business.
As far as for Hui Muslim, in the large cities, the integration is much better while in the countryside, it is not exactly so. Especially in those muslim autonomous regions or muslim dominant regions, e.g. NingXia, GanSu and etc, Hui muslims are not that nice to deal with.
ShaanXi used to have a lot of muslim hui population, while the Dunggan revolt during Qing Dynasty ended up with most muslim there got wiped out.
Islam during the Qing Dynasty - Wikipedia, the free encyclopedia
Dungan revolt (1862
Basically, no matter which religions you come from, as long as you do not challenge the government, everything can be discussed and mostly remain fine.
If you rise against the government, normally the government is very brutal to suppress such uprising, no matter it is the past dynasties or the current PRC (with the exception for the past 20 years, during which Chinese government has been quite soft most of the time).