In the United States there has been a long history of discrimination against national origin, especially of recent immigrants. Poles were just used as an example here of a national origin.

Check out

http://en.wikipedia.org/wiki/Chinese_Exclusion_Act

http://en.wikipedia.org/wiki/Japanese_American_internment

for the most blatant forms.

It's probably an example of anti-racism law.

Poles are not a race though. It's only nationality.

True, but U.S. anti-discrimination law rarely speaks directly about race, and instead uses the broader phrasing "race, color, or national origin", which covers pretty much anything race- or ethnicity-based.

Polish is an ethnicity, and also national origin. In many places in Europe anti-racism laws don't just say "race", they say "race/ethnicity"

North or South?

(I expect he'll say it was just an example, but Freud would disagree)