The point of the article is that most immigrants come from a long way from home and because of this are more likely to assimilate, more likely to adopt the US as home, more likely to shed ties to the old country than mexicans.
If you look at the pie charts, you find essentially no difference in education or employment or homeownership between native born and immigrants from everywhere but mexico.
Further, unlike other anti immigrant articles which often argues against all immigrants or all non white immigrants, this one does not do that, but says that because the homeland is so close for mexicans, it hinders their assimlation. And while arguing against mexican immigration, the article does so without prejudice, and without malice.
The author dismissed this point, but I am not so sure it should be dismissed. Once some of these areas in the SW become overwhelming Hispanic/Mexican what is stop them from voting themselves off the island, and if they do decide to will there be a national will and a Lincoln there to fight the secession?
My guess is that within the next 5-10 years you will see this come to pass in some parts of AZ, CA, NM, TX., and that the national mood driven by the DBM will be to let them leave. Once that damn is breached you can say goodbye to the US as we know it today. The World Left will finally see their dreams realized. America will cease to exist.