The quote from Tyler Cowen that Steve Sailer mentioned below ["Some people are puzzled as to how human, pig, and bird strains of the flu have mixed together, but if you have spent any time in rural Mexico the answer is obvious: these creatures all live together in close quarters."] is exactly the kind of thing that pings the Hatemeter at SPLC World Headquarters and Media Matters.
It happens that Cowen is a major immigration enthusiast, which tends to overpower his economic instincts, and that he has spent a lot of time in Mexico, and likes the people there. (So does Chilton Williamson like the people there. The difference is that the he likes them there enough to want them to stay there.)
But if Cowen were Steve Sailer or Peter Brimelow, the quote above would go in the Ransom Note Racism file and be repeated for years.