I've heard this joke before. I don't find it particularly funny. Actually, it is loathsome and against Jewish values. But considering the cases of Bernie Madoff, illicit trafficking in human organs, and the scandal of "Kosher" meatpacking plants, it's not surprising.
Hamas says Egyptian mediation has restored calm along Israel, Gaza border (Haaretz)
from the article: James Jones' Jewish joke - funny or inappropriate?