If a collision had happened, of course the Chinese ship would be at fault, but the US ship would also have to answer why they didn't also maneuver to avoid collision.
Rule 17 deals with the action of the stand-on vessel, including the provision that the stand-on vessel may "take action to avoid collision by her manoeuvre alone as soon as it becomes apparent to her that the vessel required to keep out of the way is not taking appropriate action.
The USN has a lousy track record for collisions and near misses.