Normally the US govt is too afraid of Chinese imports to criticize China (look at history of Taiwan). Trump of court is a wildcard on Twitter but his administration policies and diplomacy aren't nearly as radical. But we do have the tariff issue at the moment, which might have some background connections.

Weird that he's not tweeting about it though. Maybe because a standoff lacks the immediacy of specific punctuated incidents.

And ultimately it's an issue between one and a half foreign countries that doesn't really impact US interests so much compared to much larger issues with China.