I don't understand why I should prefer the comfort of some guy 2,000 miles away from me that I've never met over somebody on the other side of a border that some guy drew on a map a couple hundred years ago. Both of these people are abstractions to me; why should I prefer the Californian to the Chinese person? Even more to the point, why should I prefer the Californian when (in the general case, apparently not in this specific case, as cited by the OP) trading freely with the Chinese person will tend to improve the welfare of those around me to a greater degree?