Institutions or people who wish to impose power over other people must have some form of leverage. This will either be legal (you must 'obey' the police or go to jail), physical (I have a knife), resource (they pay you), cultural (she cannot wear that or she will be shunned) or intellectual (he knows something you don't.) Since religion can cross all those boundaries - and regularly does - it can only be weakened by an equal or superior opposite force. Mockery and derision attack the cultural and intellectual forces of religion. If an idea can withstand and triumph over mockery and derision then it is a worthy cultural and intellectual force (it does not make it right, just worthy).
If an idea cannot withstand derision and mockery and can only stand if aided by legal, physical or financial support then it is intrinsically unstable and weak. The true believers of a faith should relish mockery and derision. Only those deeply insecure in their belief seek to be unchallenged and hide behind squeals for respect and politeness because that allows them to continue to impose their will over you.
Religious people attempt to control and impose their will over everyone else by dictating what can be said and what can be done from basic social interactions through to state level laws. It is very rare for a religion to stand up for freedom of thought or to celebrate difference and individuality.