Chicago's Poles seem R as well. The four Cook County townships that went R are also the most Polish. Norwood Park is about 30% Polish.
Perhaps there's a Polish immigrant/Polish American difference? The Cook County Polish areas are quite immigrant (or 2nd generation), I'm sure they outnumber the Bill Swerski superfan types. It seems like third and fourth generation Polish Americans have dispersed to the collar counties or have even left the region entirely.
A good chunk of my family is Italians and other white ethnics from a Catholic background (no Poles, though). Chicago was where quite a bit of them lived for a long time. Now practically all of them have moved south. It's not too strange to imagine many Polish-Americans making the same choice.