That said, some religions are stupider than others. All have intolerant, repressive factions, but in some the violent and hateful are the mainstream while in others they are the fringe.
Islam, as it is practiced in most of the Muslim world, is the most coercive of the world's major religions, and that can be attributed to both the nature of its origins and the political and cultural histories of the counties in which it dominates.
One of the major distinctions between Islam and other faiths is that predominantly Muslim countries have not undergone the political evolution in the west that has separated religion and state. That is one of the reasons why apostasy is considered a crime punishable by death within Islam. Abandoning Islam is seen not only as a betrayal of religious belief but as treason against the state, of which many impose Sharia law as the law of the land.
Islam is a religion that, at its origins, was spread by the sword. When the basis of a religion is "worship as I say or die," it will have an understandable insecurity about being mocked or criticized. Having been born of a chauvinistic, misogynistic tribal desert culture, it is even more sensitive to insults.
The current round of violence and riots through the Islamic middle east partially drive from their confined understanding of free societies. By western standards in general and American in particular, there is no free speech and free press in the Islamic world. They have laws against blasphemy and apostasy. Journalists can be jailed or worse for criticising the government or religious institutions. Most inhabitants of Muslim countries just don't get that America doesn't operate that way. Because that's how things work for them, they assume that by not jailing people who make fun of their prophet, the American government must somehow be complicit in the insults.
In fact, many Muslim leaders who have immigrated to the west still don't really understand western concepts of free speech. A typical example comes from Toronto, Canada-based Zafar Bangash, the pro-Iranian Imam and President of the York Region Islamic Society, who said in an interview to Iranian state-controlled PRESS TV:
"I think all US officials whether they are in the Congress or in the government or elsewhere are quite familiar and aware of the fact that the honor of the Prophet of Islam is a red line for Muslims and that insulting him is basically taking a stab at the very core belief of the Muslims and that this kind of blasphemous act should not be permitted and yet US officials advance this curious notion that people have the freedom of speech and expression."What may be a 'curious notion' to Bangash is a fundamental, sacred right to Americans and most people in free societies of the sort that Islamic cleric fails to comprehend. The right of individuals to express themselves, even in poorly made, offensive, intentionally insulting movies, is guaranteed under our laws. Jesus and God himself and prophets of both of Christians and Jews are routinely made fun of in America. But no one is killed over it and that in part is a testament to the confidence of those religions and the civilized societies in which they abide.
Democracy literally means "government of the people." Islam literally means "submission." The two ideas are not compatible. Either people can be free to rule themselves or they will be forced to submit to autocratic tyrants who use religion or other means to impose their will. We may be reaching the stage where if Islam doesn't find a way of reforming, democracies will need to find a way of defending themselves from the religion that demands submission.
UPDATE - to prove the point, no one has been murdered because of this image (h/t Blazing Cat Fur)