Some issues seem to suck the brains out of people.  For example, a Jane Galt post on immigration prompted the following from commenter “john w“:

Specifically addressing immigration from Mexico, there is one issue that nobody has mentioned yet; and yet this ought to be of especial concern to those of us with Libertarian leanings >>>

Q: Why do so many Mexicans want to leave Mexico? A: Because Mexico is a poor country.

Q: Why is Mexico a poor country? A: Because they have a corrupt, authoritarian, dysfunctional government.

Q: Why does Mexico have such a bad government? A: Well, maybe there is something in Mexican culture that encourages this, or at least tolerates it.

Q: Why are we so sure that those millions of un-assimilated immigrants are not going to eventually bring that tolerance for dysfunctional government with them, and to eventually drag the US government down to the level of the Mexican government? (emphasis mine)

A) Because this same type of charge has been thrown at virtually every new wave of immigrants and been proven wrong each time (heard any complaints about Italians lately?).
As for the bit about Mexican culture supposedly uniquely encouraging outright kleptocracy: by that logic any american ex-pats that move abroad should be deported.  After all, we might spread cooties xenophobia, corporatism, and tolerance of weak beer.