The US does not observe the free-trade principles. Those are for the weak. So agribusiness is highly subsidized and pours product into Mexico and drives out Mexican farmers. Maybe they have to go into the cities, and they don't have jobs to support them, so they flee across the border.
The great artist is a formulation of the greatest intelligence: he is the recipient of sensations which are the most delicate and consequently the most invisible expressions of the brain.