Many of today's advocates of "free trade" (regardless of party) support it for the same reason that Marx supported it: the demise of the nation state. Like Marxists, today's elites want a transnational order in which individual nations and cultures are obsolete. This is also the reason why the elites want to open our borders to the Third World. Support for liberal immigration policy and "free trade" are like ideological litmus tests for being part of the elite political establishment.
The only difference between them and Marxists is in their vision of who/what replaces that nation state. The Marxists wanted a "revolutionary proletariat", while the Davos crowd wants to replace the nation state with transnational corporations and the bureaucracies that cater to their needs.
I suspect that’s exactly the case. And that’s why both Marxists and the Davos crowd see a patriot and economic nationalist as their bitter enemy.