So I guess it's not just that we aren't supposed to draw pictures of Mohammed as terrorist, or of Mohammed at all; we aren't even supposed to draw pictures that are obviously not of Mohammed, and that are meant to mock the inability to draw pictures of Mohammed.
Well, I have to admit: The folks who are offended by this have a First Amendment right to be offended. They should feel entirely free to be offended.
The rest of us should feel entirely free, as a matter of civility as well as of law, to say: Your decision to be offended by this particular cartoon gives you no rights (again, as a matter of civility as well as of law) to tell us to stop printing it.
More on the underlying conceptual issue — the difficult but necessary distinction between (more or less) reasonable taking of offense and unreasonable taking of offense — later; I also hope then to talk in some measure about the distinction between this cartoon and others that I do think can reasonably be found to be offensive, and that probably shouldn't (as a matter of civility) have been published in the first instance, though it is proper to publish them now in order to explain the controversy. For now, it seems to me that this incident does plenty to illustrate the danger of the "it's wrong to publish any cartoons that offend people" attitude.
Particularly as those who espouse this attitude don't really mean it.