OldRoadrunner:
(people)..."need to understand that our immigration policies favor college-educated, middle-class people who happen to be white."
Horse manure. That was true 50-80 years ago, but Not in the Last 30 years. I have personal knowledge of this - My (now-EX) wife came from Brasil 25 years ago. She is not "white". She came on a Student Visa...met Me...and the rest is history.
The Fact that ICE has a "OTM" designation ("Other Than Mexican") shows a official distinction and "hands off" towards poor ILLEGAL immigrants.
Illegal Immigrants already earn more than minimum wage in agriculture.
There are many desperate US Citizen Homeless. Do you want to leave the door off your house to accommodate them? So they may freely come and go as they please? I doubt that. 
WE can Not Help the Whole World, we are Broke. No matter how much some politicians want to be Champions of ILLEGAL Mexican  Immigrants (Using OUR Money, of course) we simply can't afford it.