Some of them truly are. I saw that first hand during my service as a member of the local library board and, eventually, its president. They are often flamingly liberal, manipulative of their patrons, whining, grasping, and self serving. The range of behaviors I witnessed went from keeping conservative books out of the library to monopolizing "best sellers" for themselves. The waiting list for the most popular books was often 2 years long. I ripped up my library card after I left the board, I was so disgusted.
Wow! I still have a memory of the old lady librarians who had hair tied in buns and orthopedic shoes. They were vicious! And who can forget the mean librarian in “A Tree Grows in Brooklyn” who never once had a kind word for Francie?
Do we have a new horror genre here?