Like it or not, most of the immigrants of the past 150 years have been the "losers" from their native countries. Otherwise, why would they come here?
There are only two relevant questions to be answered w/r/t immigration: (1) Should the U.S. get to decide who comes in? and (2) Should we use rational criteria? When those two questions are answered correctly, everything else falls quickly into place. The U.S. taxpayer has no obligation to support the world's flotsam and jetsam, even if some of them are able to sneak across our borders.