One of the earlier negative stereotypes of Poles was the comic-strip character Joe Palooka (Pałuka), a good-natured but stupid prizefighter, which predated Ameica's 'Pollack jokes' of the 1970s
BS. His character was based on Pete Latzo whom he allegedly met outside of a poolroom. It's a hell of a stretch on your part, for the character to be Polish his surname would have to be (Pałka not Pałuka) as suggested by you. Besides as a slang term "palooka" has many meanings but in the boxing world at that time the term "palooka" was used to describe a third-rate prizefighter and that's how it would have been perceived by the readers at that time. It still does, take a good look at the end of this scene, though the modern slang meanings fit in quiet well too.