Bull crap.
But, in general, the protective system of our day is conservative, while the free trade system is destructive. It breaks up old nationalities and pushes the antagonism of the proletariat and the bourgeoisie to the extreme point. In a word, the free trade system hastens the social revolution. It is in this revolutionary sense alone, gentlemen, that I vote in favor of free trade.
-- Karl Marx 1848
When I say actual Marxists, I mean actual communist regimes. Name me an actual communist regime that has free trade. And when I say communist regime, I don't mean a country like China, which has a stock market, private property and private corporations that make products and hire people. I mean a regime where the state is the ultimate maker of goods and the ultimate employer of labor, where decisions on purchasing, production and hiring are made by party cadres. Does Cuba have free trade? Does North Korea?
The fact that Karl Marx liked free trade for his own reasons doesn't mean that Keynes and Friedman were wrong. Marx was wrong about a lot of things. If he was wrong about the ultimate victory of Marxism, why would anyone assume that he is right about free trade being an asset to his cause?