Don't we all remember how the Patriot Act was being used to get lists of books read by potential terrorists and how librarians were aghast at this?
It's very possible they wrote themselves very strict guidelines in order to support their beliefs in not revealing book lists to government authorities.
The guidelines were probably written just a bit too strict and may need to be opened up a bit.
I guess we could go with the practical advice of not getting library cards for children, but I remember that getting my first library card was a seminal moment for me and got me really excited about reading. So taking away that experience would be kinda sad.
I think this is probably more a result of unintended consequences rather than some malicious scheme to undermine parental rights.
Read the two links before you come to this conclusion.