For Xinjiang, as far as I know, terrorism has started even before WTC, that's why the US even put ETIM in the terror list in 2004. For a long time, the US largely couldn't care about the uyghurs. Only for the past year or so, the US begin to use the uyghurs as pawn in its chess game with China. Certainly, for the past few years, terror attacks have largely died out in Xinjiang. So I don't think the US is the culprit here. Not to mention for the 2011-2016, the US is busy with its own war on terror.

As for HK, yeah, I could agree with you that the US is involved in it, maybe even ignited it.