It's western propaganda, most Uighurs are very content with the government, and of course every big countries more or less has minority issues, China is of no exception. China's biggest Muslim group is not Uighur, it's Hui Muslims, who live peacefully in China and never cause any problems. A handful of seperatists don't represent the whole majority. The great majority of Uighurs, Mongols, Tibetans don't have problem with the Chinese government.
The only one is being brainwashed is you. I lived in several countries and I know how they brain wash you with fake news about China. Almost all foreign expats living in China agree that foreign media is lying through their teeth.