In his wonderful blog, The Volokh Conspiracy, law prof. Eugene Volokh has put forth an idea that I think is a real breakthrough in the our understanding of the dynamics of free speech and censorship. Suppose you are a European Muslim, deeply offended by the publication (and republication, and republication) of those cartoons. European Christians and Jews tell you that they feel your pain, but you must bear it as part of the cost of freedom. But your country does have a law against denying the holocaust. The Jews don't have to pay the "cost of freedom," but you do! Thus the bitter resentment of the uneven way these costs are distributed: censorship envy!
The same would happen in this country if we passed a constitutional amendment banning flag burning. It would be hard to tell Muslim Americans, "Get used to it, buddy, sometimes freedom hurts!" "Funny how it doesn't seem to be hurting you!" they would say.
BTW, this helps to explain something that advocates of censorship often find hard to understand: That their opponents tend to make "fetishes" of extreme cases. "Why to do care about whether people can burn the flag (deny the holocaust, use the word "Nigger," etc.)? Don't you detest that sort of behavior? Sure we do, but if we ban the speech we hate, we give others a passionate motive to ban the speech they hate.
We see this motive in a particularly nasty form in the Iranian newspaper that is seeking cartoons "humorously" dealing with the holocaust (mainly by suggesting that it never happened, probably). For a lot of European intellectuals, this gesture puts them in a tough position. On the one hand, they defended their mainstream press's right to publish the cartoons lampooning Mohammed, on the other hand they defend their governments' laws censoring holocaust deniers. Why is the first a case of free speech while the latter is not?
In the US, where the mainstream press did not publish the cartoons, and where the Bill of Rights makes holocaust denial laws illegal, we do not have that problem. We can attack the Iranian newspaper's viciously ignorant gesture without lugging around so much baggage of our own.