My view in a few words.
Other things being equal, one should not mock, deride, or engage in any sort of unprovoked verbal or pictorial assault on people or the beliefs they cherish. So if Muslims were as benign as Christians or Buddhists, I would object on moral grounds to the depiction and mockery of the man Muslims call the Prophet despite the legality of so doing. But things are not equal. Radical Islam is the main threat to civilized values in the world today. Deny that, and you are delusional as Sam Harris says. The radicals are testing us and provoking us. We must respond with mockery and derision at a bare minimum. The 'Use it or lose it' principle applies not only to one's body, but to one's rights as well. For the defense of liberty, the enemies of our rights must be in our sights, figuratively at least, and this includes radical Islam's leftist enablers.
Hillary, for example, who won't even call it what it is.