I think that "protecting" children from knowledge is an ill-conceived idea. If you are going to attempt anything of the sort, you should be required to first show that harm is in fact caused by the thing you are trying to "protect" them from.
As this has not been done, we should not censor such things.
I'm going to provide a personal anecdote. When I was 5 or so, I saw a news special on how children got their feet caught in escalators and had to have them amputated.
I'm still terrified of escalators. I'm one of those people you can see wearing a heavy backpack and still running a suitcase half his size (full of books, I might add) up four flights of stairs. I can officially tell you that that particular piece of knowledge was to my detriment. Might have been a good idea for my mother to keep me from watching the evening news all the time, no?
And no, it's not like being aware about the Danger of Escalators was helpful/neutral. It mostly led to me being a pile of paranoia.
How about exposing children to violence in media? Is that a good thing? Should we allow harlequin romances (or French novels like L'Etranger [The Stranger], if you're looking for something a bit more highbrow) on first-graders' bookshelves, for those who are capable of reading them?
Simply put, they're age-inappropriate. If I had a kid, I wouldn't let her anywhere near that sort of shit until I knew she could handle it. That's right--little Victoria isn't allowed to read novels with graphic sex or violence until I've figured out whether or not she's as crazy as I was at that age.