What do you mean, “what happened to” parents deciding what books are placed in the children’s section of a library? That has never been the case. There is no committee of parents meeting to decide on whether each book is appropriate for everyone’s kids. It’s a library. If a parent doesn’t approve of the book their child wants to check out they say “no.” It’s as simple as that. These are children’s books, they will be put in libraries in the children’s section.