I totally agree that Mormonism used to be a rather terrible and violent religion. But please notice that you had to go back over 150 years to find such an atrocity committed by the Mormons. Their religion has changed drastically since then, thanks to collisions with secularism. Christianity used to be more barbarous as well, but centuries of progress have tamed it significantly.

Let me give a more obvious example of religion's role in encouraging/discouraging violence: Jainism. The core contributor to Jainism, Mahavira, said, "All breathing, existing, living, sentient creatures should not be slain, nor treated with violence, nor abused, nor tormented, nor driven away." It is really hard to be violent as a Jain. Jains protest by fasting. In fact, Gandhi got many of his ideas about nonviolent resistance from the Jains.

Also, you didn't answer my question. Do you honestly think there is any religion besides Islam that would raise such security concerns if mocked in a Broadway musical? I agree that culture and other factors matter, but the doctrines of religions are quite different. Some of those doctrines call for violence more than others. The sooner we admit that, the sooner we can try to fix the problem.