That is part of the System - Free Trade means Free Moving of Goods & People in both Directions - sorry if it is hard to accept but 1/6 of Humanity could support (with robotic, highly mechanized Work) the Remaining 5/6 with Goods...
The work is free to move, and it moves to the cheapest point on earth. If you would replace the Workers on the Farms & in the Factorys (who get a third world Pay anyway) with Americans, the result would only be a) bankrupt or b) moving of the Factory/Farm into another Country. So this thing is nothing unexpected- such stuff happens when "subventions" fall, taxes on goods are erased and borders are opened by Force of the Market (this (all of the sudden) evil thing workx bothsides... bloodyhell, how surprising

What do we learn out of it ? Nothing. Can we change the Situation ? Nope.
So what to do ? Blame Canada! Mexicans are in Truth disguised Canadians!!


