If you take race — language is a different matter, by the way — into account, Jonah, you are engaging in racial discrimination, even if you consider other factors, too (cf. university admissions). Now, I did not say that engaging in such discrimination is “crazy”; indeed, I suggested that it might well be “rational” for Arizona cops to do so. But that doesn’t mean it’s good policy.
As a statistical matter, Jews were more likely than non-Jews to be Communists. It would have been quite rational, therefore, for the FBI to have a policy of focusing more heavily on Jews in its counterespionage investigations, and to ask them for additional evidence that they had no ties with the Communist Party. But I would have opposed such a policy, because the cost of such institutionalized and divisive discrimination is too high. And that’s in the context of counterespionage. Here, as I say, the most the Arizona police hope to accomplish is to catch people who are here looking for work. It’s just not worth it.