I think you interpreted my post too narrowly. Censorship is good in many situations. I don't let my two year old watch horror movies. Prevention of the publication of illegal images and documents.
What you do with your son is not censorship. And stating that it is good to censor "illegal" images and documents is circular logic. Governments always declare as "illegal" the ideas that they want to censor. They don't censor "legal images and documents."
Censorship is never a good thing. The dissemination of ideas is a good thing, and the marketplace of ideas will weed out the bad ideas. If the marketplace of ideas cannot squash out an idea that you think is bad, then it's because enough people like the idea. Absent national security considerations, the government has no business being in the "you can read this but not that" business (even obscenity laws have essentially faded away after a long string of narrowing supreme court decisions - what's left is usually to protect the people depicted/victimized, not to prevent the spread of the idea).