How much of a threat do the Uighurs present to them? Not much, I'd wager. Totalitarian regimes like unrest. It gives them an excuse to expand their power.
The ChiComs are not our ally. We should never make the mistake of confusing them for one.
I agree--mostly.
But, there are all kinds of alliances. What I've speculated about here is rather a small and narrowly defined alliance--and then, only as a possibility.