Ray Bradbury, the sf writer, who penned one of the most memorable works in that genre, Fahrenheit 451, which was about a society that ordered all books burned had this to say when he was asked whether his book should be sanitized so as not to offend the young readers of today. Here's part of his response:
There is more than one way to burn a book. And the world is full of people running about with lit matches. Every minority, be it Baptist / Unitarian/ Irish / Italian / Octogenarian / Zen Buddhist/ Zionist/Seventh-day Adventist/ Women’s Lib/ Republican/ Mattachine/ Four Square Gospel feels it has the will, the right, the duty to douse the kerosene, light the fuse. Every dimwit editor who sees himself as the source of all dreary blanc-mange plain porridge unleavened literature, licks his guillotine and eyes the neck of any author who dares to speak above a whisper or write above a nursery rhyme.This is what any author would say, isn't it? Tart, but true. Oh, Lord, preserve us from the True Believers who are bound and determined to make us all holy, even if it kills us.
UPDATE I: Here is another good article on this whole subject of bowdlerizing Huck Finn and other classics.