This is a tricky question. It is agreed that the abuse of children is wrong. However this is a question of morals and it easy to have an immediate emotional response of "no child porn" and that's it. However can we say that for everything? Medical books may have the anatomy of naked children in them but is this wrong? No, it a tool to learn. But what about entertainment? Is it wrong to watch a child porn snuff film? Yes! But, Is it wrong to read a book where a major plot point is child abuse? No.
There is no definitive answer to this question. It a big fuzzy gray like that we don't want cross. I would like to live in a society that dose not see every issue as being all right or all wrong.