You'd think so, yes. Of course there is such a thing as age-appropriate books - and I say that as someone perhaps more inclined to find certain things appropriate at a given age than you are - and so it should be asked which libraries those books are banned from, and whether their being present in a library means any child, including young ones, can read them. If the banning of that "Speak" book was just to keep it out of the hands of 8-year olds, well, I haven't read the book, but that might not be so unreasonable. Even the marvelous TKaM might go a bit far for children of that age who are good enough readers to want to try it. I came across Stephen King's review of Order of the Phoenix today, in which he quotes his mother's rule of thumb, which was (paraphrased) that if a child was a good enough reader to read a given book, she saw no reason to forbid that on account of the content; except if she thought it would cause nightmares. I don't know if I'd go as far as that myself.