I mean if "in the long run china is going to win that area" and at the moment US agencies are supporting a different group to counter who China supports, it seems like it will escalate to opose China's growing sphere of influence.

Those escalations from legitimate grievances and protests for democratic freedom are often pushed along by imperialists towards colour revolutions and then towards proxy wars. It's not always - and for the sake of the Thai people I hope it doesn't become that - but it's a possibility and I dont know if either side can be supported except for harm reduction purposes.