Muslim extremists have, of course, made death threats against cartoonists in Denmark and elsewhere. Politicians like Turkey’s Erdogan have been disappointingly thin-skinned. But it still came as a surprise when some young men in Paris actually murdered cartoonists in a satirical magazine. After all, cartoonists are the class clowns, the jesters. They are protected by their humour and the expectation that they’ll be scallywags. No?