It was not funny at all. I think Jerry was doing 2 things with it : one saying "Ha , I am on top fuck you all" and secondly he showed all his fans what selfish pricks all the characters really were. In the show they are standing around watching the fat guy get robbed, laughing at him being fat, saying maybe if he lost hi smoney he could not buy food and could afford to miss a meal.
At the end Jerry is in prison doing a stand up comedy act with unfunny material like "Whats with weight lifting in prison? Isn't the sodomy punishment enough?" or something like that...nobody laughs, and one of the convicts in the audience says "I am gonna cut you".