Great post. The argument against free trade is that other countries are not giving the US exporters the same access to their markets that the US gives to them. This is usually offset by a countervailing duty or tariff. You are right that free trade benefits all countries because it increases total welfare through lower prices for consumers abeit at the expense of the industries which lose jobs due to lack of comparative advantage.
This is one of the great features of cryptocurrency is that it cuts out the regulatory agencies which want to politicize the market place and extract value to perpetuate bureaucracy. Although free trade is better, some government will get in the way. This is why the wto was established from gaat. Now that seems to be in peril due to the lack of enforcement of intellectual property rights. One country can't promote free trade while another has the doors locked even though economic theory shows it benefits all countries. The best solution is to have your own free trade with cryptocurrency, gold, and silver ...the parallel economy.