Also the seller's claim that direct doesn't add anything to the economy is false. That surplus will be directed elsewhere, hopefully to something more productive than what has become an unnecessary intermediary.
Take that subsidy away. If the intermediate seller can still survive, then he is still providing some economic benefit.
The surplus comes from the fact that US buyers don't have to pay a percentage to the intermediary, so they can spend it on other things, like going out to a local restaurant more often.
A contrived example...
A person has $X that they spend every week at the local town restaurant. They see they can buy a cool new widget from a Chinese vendor (from the article) for $Y. Over the course of the next few weeks, said person spends a little less at the restaurant so as to save up $Y, ultimately purchasing the widget once enough money is saved.
In this example the person is contributing less to the local economy.
Though I don't see introducing/enforcing waste as a right way to ensure more money goes to the national economy.
I guess the question then is: do we have a way of predicting which way it will go?