One of the most pernicious forms of attempted censorship of unwelcome views isn't overt repression, but rather to convince people not to express those unwelcome views in the first place. It's always much better to head off the wrong thoughts before they are expressed rather than clamp down on them after they are already out in public. Why employ the blunt instrument of state repression if people can be convinced to repress themselves?
This is precisely what happens with unwelcome criticisms of religion, especially in the West where nations have little to no authority to officially censor material that is critical of religion. The most common excuse is to claim that non-adherents of a religion should not "offend" religious believers by criticizing their faith. This argument is based on the idea that criticism of a belief system is the same as a personal attack on the believers. Sometimes, and in some cases, such a connection may be valid -- but for the most part it is not.
Believers insist that they and their religion should be respected and, therefore, that attacks on religion are not a valid use of one's free speech rights. However mush respect a person might deserve as a human being, though, that doesn't mean that their beliefs themselves deserve automatic respect as well. Beliefs have to earn respect; many actually earn disrespect.
Beliefs which are true and valid cannot be harmed by criticism, even by unfair and incorrect criticism. Beliefs which are not true or valid will only be revealed through criticism. What this means is that if we care about the truth, we should welcome criticism of even our most treasured beliefs: if they are true then this will strengthen us; if they are wrong, then we will know and be free to follow new beliefs.
Attacks on free speech have most recently come primarily from Muslims. Some threaten violence if ideas, images, or words which they find offensive are given public expression. Others deplore both threats and actual violence, but they are perfectly willing to benefit from them and are no less eager to insist that criticisms of their religion are offensive and should not be permitted under the cover of "free speech." They don't seem to realize that the free speech which protects their critics protects them as well.
This image is based on a World War II poster ordering people to keep quiet in order not to reveal war secrets to possible enemy spies.