I really like the clarity and point of view in this short 2006 essay by Ronald Dworkin, American philosopher and scholar of constitutional law. The essay is relevant in light of both Perumal Murugan and Charlie Hebdo incidents.
So in a democracy no one, however powerful or impotent, can have a right not to be insulted or offended. That principle is of particular importance in a nation that strives for racial and ethnic fairness. If weak or unpopular minorities wish to be protected from economic or legal discrimination by law—if they wish laws enacted that prohibit discrimination against them in employment, for instance—then they must be willing to tolerate whatever insults or ridicule people who oppose such legislation wish to offer to their fellow voters, because only a community that permits such insult as part of public debate may legitimately adopt such laws. If we expect bigots to accept the verdict of the majority once the majority has spoken, then we must permit them to express their bigotry in the process whose verdict we ask them to accept. Whatever multiculturalism means—whatever it means to call for increased “respect” for all citizens and groups—these virtues would be self-defeating if they were thought to justify official censorship.
Muslims who are outraged by the Danish cartoons note that in several European countries it is a crime publicly to deny, as the president of Iran has denied, that the Holocaust ever took place. They say that Western concern for free speech is therefore only self-serving hypocrisy, and they have a point. But of course the remedy is not to make the compromise of democratic legitimacy even greater than it already is but to work toward a new understanding of the European Convention on Human Rights that would strike down the Holocaust-denial law and similar laws across Europe for what they are: violations of the freedom of speech that that convention demands.