I have read much of the book, but I’ve yet to find a good chuckle. This narrative is typical:
Waehrend der Eingeborenenaufstaende in Deutsch-Ostafrika erlaesst das Kaiserliche Ministerium in Berlin folgende Anweisung an die zustaendigen Stellen: "Die Eingeborenen sind dahingehend zu instruieren, dass sie under Androhung schwerer Strafen jeden Aufstand sechs Wochen vor Ausbruch schriftlich anzumelden haben!"
Translation drains away the "humor," but it uses awkward bureaucratic language to report that "the natives" in East Africa have been told that if they wish to revolt, they must first submit six weeks written notice. If there is anything vaguely funny about this, it concerns how the German language can formalize even very brutal topics, alternatively a simple German street sign can become ridiculous through long constructions and the use of the passive voice. But I don’t think that was the point of the joke, which I take to be mocking the German bureaucracy.
Moral issues aside, I believe the Nazi jokes are not funny because of their monotone nature, their lack of irony, and the lack of reflective humor behind the putdowns. A victimized group will be mentioned, and put immediately in a subordinate position, but only rarely is that group the direct butt of the joke. The oppressed group is there en passant, so to speak. The resulting incongruity is scary rather than funny and I suspect this would remain the case even if we were not well-informed about what the Nazis did.
Charlie Chaplin’s The Great Dictator, while scary, is also funny in parts. It mocks the ridiculous element in Hitler. The Nazi jokes have a huge and ridiculous elephant(s) in the room, so to speak, but by refusing to mock those beasts the rest of the joke almost certainly cannot be funny.
The chapter on the Holocaust is of course chilling.
It can be argued that no one should write a book "reselling" and thus profiting from Nazi jokes (or for that matter blogging them). I take this point of view seriously, though ultimately I believe the story should be told.
The tough part is that good humor is often brutal rather than morally pure, so the question remains what exactly distinguishes funny brutality from unfunny brutality.
Social scientists do not devote enough attention to the phenomenon of humor, and I found this book one of the better places to start.