I don't think culture war stuff is particularly appropriate here, but to provide some more useful discussion/context about the southern border, about half of illegal migrants enter legally and simply overstay their visas. Of those who do cross the border, about 80% are caught and arrested. The southern border also stretches through some of the harshest terrain on earth and most of the bits remotely near populated areas are heavily fortified. Crossing the border is the closest thing I've seen to the DMZ outside Korea. Those who cross far outside populated areas are putting themselves at incredible personal (and financial) risk.