Except insane.
If we know something is insulting because someone tells us it's insulting, and we keep doing it, we really don't care if it insults them, do we?
IOW, we really don't care about them at all.
Immaturity has caused these extreme reactions, and it will take a certain level of maturity to bring them to an end.
Except insane.
Publishing cartoons that offend, if you don't believe the message, would simply be a cruel exersize.
If the cartoons accurately depict your opinion of the world, then offense is required. People have a right to express negative opinions of the muslim faith.
You might as well insist that all of our women cover themselves, because we KNOW that having them walk around uncovered offends our muslim brethren.
Which is to say -- let's not be deliberately offensive for no purpose, but let's not temper our liberties at the behest of a theocratic movement seeking to impose their religious tenets on us. Because the "no pictures of the Prophet" rule is simply a tenet of their faith, just like the rules about women, and the rules about publicly showing faith for another religion, and drinking, and a bunch of other rules.
Why would you think that, having successfully gotten us to follow any of the tenets of their faith through violence, that they would stop until we all lived in a muslim theocratic state? Which is, by the way, what many muslim leaders preach for our future.