I can't fault some poor person from another country for coming to the US to try to make a better living than they could where they came from. If I were in their position, I might very well do the same.

I can fault big corporations for not only screwing over US workers by using foreign labor to drive wages down, but for also screwing over foreign laborers by paying them substandard wages and using work visas as a way to hold them over a barrel. Greedy fucks.