Gimme a break. MOST of us know what he meant. You don't see Lawyers, Doctors or Software Engineers swimming across the river.
I've been to the back parts of Mexico and seen how these people live, and I don't blame them. No water, no power, dirt floors, "homes" built out of scrap plywood and corrugated tin sheets. It's terrible, but a testament to socialism. If I was under those circumstances, I'd swim too.
However, a large percentage of these people are generally uneducated, at least somewhat illiterate, that is all he meant.
And yes, some are criminals, just look at the MS-13 and other gangs. Drug cartels, most heroine comes in that way, and now fentanyl! A kid that grew up calling me his uncle recently died from an overdose of that crap. Those dealers should be charged with murder.