You're right, China was, not sure if you could claim it still is, suffering from an Islamic insurgency that was trying to form an Islamic caliphate. The Chinese government imprisoned 1M people in an attempt to prevent the success of that insurgency. They clearly went too far.

Around the same time the Chinese government started imprisoning Muslims, the US government started killing or was at the very least was a direct cause in the death of 1M muslims, not to stop violence but for revenge.

Oh and as far as concentration camps are concerned, there's a bunch of brown skinned kids in cages that would like a word