I am also of Polish descent, and all the good jokes circulated the Polish neighborhood. Of course, I am also from Chicago, and we didn't tell Irish jokes; we elected them.
I think the point is: if you're Polish you can make fun of Poles; Irish, the Irish; a Jew, the Jews. Mr. Langlieb is Jewish, so his satire should've been directed at his own. Otherwise, it's clearly meant to be insulting; or do you think vermin is a satirical term of endearment?