Earlier quoted context omitted.
So, this supply and demand thing. We keep hearing from large tech companies that there's a crisis -- a massive shortage of qualified software engineers, to such a degree that they won't be able to operate at all if they can't raise the H1-B quotas and import more people to fill all the jobs currently going unfilled. If that truly is the case, then supply and demand would tell us that currently engineers are underpaid…
A similar issue exists with respect to illegal immigration and low-pay, low-status jobs such as crop picking, meat-packing, and janitorial services: if there aren't enough Americans willing to do the job at prevailing wages, then aren't prevailing wages too low? Sure, my tomatoes would cost more and cleaning services might be 200% more expensive, but that's just the cost of doing business.
With immigration Americans get cheaper tomatoes and unAmericans get comparatively better jobs. It's a win-win.