"The whole principle is wrong; it's like demanding that grown men live on skim milk because the baby can't eat steak." - Not Mark Twain
The quote above, commonly misattributed to Mark Twain, is in response to to censorship. Like the quote suggests, it does seem true that the argument for censorship boils down to its enforcement to prevent the moral, or other sort of, corruption of minors. There are socially accepted views which should be established in minors and there are those that should be kept from them. In this day and age I doubt there is much support for moral censorship in regard to adults.
It seems that there are two child rearing philosophies that would put parents on one or another side of the child censorship debate. One was already sketched above, that children need to be protected from deviant views. The other, which could be cautiously deemed the 'liberal' approach, assumes that people can think from a vantage point beyond particular belief systems, and should develop this impartial mind set. In contrast with the first view on child rearing, it would actually encourage a child to explore diverse belief systems so he can become intelligently impartial.
Personally I have serious doubts that any human can be impartial or not hold any socially motivated views. Despite this, however, second theory of child raising hopefully results in a certain consciousness of other viewpoints which I believe is a positive one. Censorship for minors, unless you are attempting to impose ideological purity, is unnecessary and theoretically damaging for an open society.