We use signs and symbols for the things we say. We live in a sea of discourse. The need to control discourse is related to fear. It's all about putting everything in its proper place. Librarians represent fears we have of institutions.
People are afraid of libraries and librarians.
The media likens libraries to crypts, catacombs and labyrinths. Those who dare walk through those massive doors are subject to getting lost. They need the expertise and direction of the librarian. Librarians control their domain. They maintain order and control.