I think they may have overreacted with conscious foresight. The point is that it isn't funny, there's no humour in it at all, and to start a flame thread in the "no sense of humor" vein is almost as boring. (Yes, I'm bored I 'm still at work.) I can't tell you how many times all Americans have been told not to tell that stupid joke because its not funny and "we will make you pay for it if you tell it" has been the message. That's been a rule much longer than 9/11. If people want to bring that kind of humor to enlighten boring Americans, well, same rules apply I guess. Think of a different, funny joke, after all these years. That's all they're asking, I think.