ida, I disagree. Obviously my last post compressed things a lot; but I believe there is indeed a common thread running through Jewish history that does link anti-Jewish jokes to anti-Jewish pogroms.
Jews themselves may well tell such jokes, and other Jews may laugh at them, but then Jews have nothing to fear from other Jews. It's when the identity of the teller of the joke is unknown that it becomes troublesome. In this case, it could for instance have been someone from the National Front. Would the joke sound so funny coming from, say, Nick Griffin or David Irving? Or the Iranian president? Would it be 'just a joke'?