I keep making that point, and people who don't want to see it, just don't see it.
It's frustrating. The height of Irish immigration was the mid-19th century, when we still had 20 or so states yet to be even formed. We needed
numbers to fill a country that still was largely empty in many places.
On top of that, prior waves of immigration were during a period without social welfare programs, and without even public education in many places. All you got was an opportunity, and had to bust your ass if you wanted to survive. That is simply no longer true.
It's not that Mexicans are different from the Irish. It's that the United States of 2018 is not the United States of 1918, or 1868.