Think back to the witchhunts and heretic burnings of medieval europe. It took a lot of courage back then to defy the religious authorities.
Then the invention of the printing press led to the Protestant Reformation and the world changed.
Today's Islam is as stuck in a medieval mindset as when it was founded. There have been subtle critics of Islam - Sufis - who got themselves in trouble with the religious leaders and some of them were put to death. Criticism of the word of the prophet is not tolerated - a "fatwa" is issued calling the for death of the offender, just as is was for Salman Rushdie.