There is no "duty" of individual self-censorship except in a police state. Why should I have to censor myself every time there is the slightest possibility someone might be "offended?" Tough luck. I don't call for restrictions on the speech of others any more than I call upon them to restrict mine.
Yelling "fire" in a crowded theater isn't a good analogy. The sole purpose of such yelling is to trigger a panic. By contrast, criticizing (or "mocking") Islam, the critic isn't trying to create a chaotic situation in the present moment.