The things that makes me mad is the use of the Cubans. I think most of those who are critical of the Mexicans streaming over don't mind accepting Cubans who are escaping an oppressive communist country. I have seen some FReepers question this policy, but most have no problem with it.
Personally I'd prefer to dispense with the whole ban on trade with Cuba. If we can deal/trade with China, Vietnam, and a bunch of "allies" in the Middle East (never mind the EU), why the heck not Cuba?