I think this is something that needs repeating over and over again. When someone tries to prevent a child from acquiring knowledge or even a vicarious experience, we place kids at risk. As adults we should want to have the chance to talk about the tough issues and topics. As adults, we should be pleased that there are safe places within the covers of a book where kids can experience the injustices, horrors, and even dangers of the world in which they live. As adults we need to help kids confront and not resign, to recognize and not remain unaware (and blissfully unaware might be even worse).
I think there is a certain amount of trust established adult to young reader as well. I want readers to trust me.