Silencing an unpopular or even offensive point of view as the National Portrait Gallery is currently being pressured to do does not justify or excuse censorship. In fact, I think you'd be hard-pressed to find many censorship campaigns that did not claim to be acting on behalf of the People, usually a majority suppressing the dissenting voice of a minority. Inserting a sensitivity clause into the First Amendment was something the founders could have done but wisely chose not to. And by the way, if we don't defend speech we disagree with, then freedom of speech doesn't really mean much does it? Popular speech needs no protection - it's popular!
And let's not forget that history is full of voices that spoke words that offended the majority of their time but were in fact correct.
Galileo seemed to be contradicting Scripture and the majority of his time who "knew" that the earth was stationary and the sun revolved around it. He was censored.
Mark Twain questioned the morality of slavery and the arbitrary taboo of interracial friendship, offending the majority of his time in his book Huckleberry Finn (a work some school systems in the United States, conservative Christian ones still want to ban).
When Margaret Sanger opened a clinic to help poor women take control of their reproductive lives, she was almost arrested for violating the Comstock Law of 1873 that prohibited discussion or dissemination of information about contraceptives as "obscene." It would not be until 1966 that the Supreme Court recognized the right of (married) couples to use contraception! Yet these ideas were considered as offensive to the majorities in their time.
When Martin Luther King spoke out against racism, poverty, and the Vietnam War (which he saw as interwoven), he was condemned as a communist (Glenn Beck would have been proud). Even LBJ, who parted ways with MLK over Vietnam, referred to him at one point using the n-word.
And of course we can go back much farther to a long line of moral leaders who were condemned in their time for saying unpopular, even offensive things, such as that the rich would have a harder time getting into heaven than a camel getting through the eye of a needle, or that we will be judged by how we treat the least among us. That sort of thing.
And while we are speaking of offensive free speech, let's consider that book found free in most hotel rooms. In this story, you'll find several cases of infanticide, incest, drunkenness, debauchery, mass murder, slaughter of innocents (and their animals), and a fairly detailed account of one (censored) man's torture and execution... which brings us of course to the ants.
I personally fail to see how ants on a corpse are as offensive as, say, graphic pictures of Sebastian riddled with arrows (I counted at least 12 in the Louvre alone), beheaded John the Baptists, and more punctured, bleeding, broken, suffering Jesus's than I think is healthy for any small child (or adult) to see. I remember walking into a room in a museum in Florence to see a giant picture depicting in gleeful detail the torment of several people being burned alive in an auto de fe. Now the spiritual descendants of those engaging in this cruelty - and depicting it in such apologetically graphic terms - want to remove a work of art because it has some insects? Give me a break!
I do not advocate censorship of the more violent and divisive imagery thrust upon us by a religious "majority" (although most accept without thinking too much about it, such as why the nails went through the palms rather than the wrists or why blood would have spurted several feet (as one particularly gory painting in Rome illustrated) when a soldier pierced Jesus's side even though it had been established that he was "already dead"). I would prefer not to have my view of a beautiful mountain-top marred by a wood carving of a corpse nailed to a piece of wood, as recently happened near Zermatt, but understand the religious organization that put up the memorial has a right to free speech, even if it may offend me and disturb small children (or adults who think about it much).