"Some American Jews" tells the truth about the very nature of this type of humour. Holocaust jokes about Jews were very popular not long time ago among some Poles. I never found them funny and expressed my dislike openly making some people's eyes go very big. Using expressions like "verimin" in relation to an ethnic group doesn't have anything to do with PC or satire.
My dear Jewish friend once caught me off guard and wordlessly stunned as when we were constructing his new home and the installers were fitting out the MBath shower - he said it was "big enough to gas the little Jew" and it broke my heart (or thumping gizzard). When I told him, he laughed it off and apologized if I WAS HURT.
Sometimes, those jokes are more disturbing to the acquainted than to the intended.