Why?
Intelligence, creativity spawned from consuming life from the minds of others.
Restrictions and disciplinarian view where talking is forbidden and being seen and not heard (the men) is very very important.
Shhh .... (but but) .... Shhhh
I am talking and I am allowed to and you are not. So be a good "boy" and educate yourself, for when you are done "you maybe interesting enough for me".
It almost makes me inspired to write an erotic poem :)
But for the guys, remember, this is a human being doing a job for the betterment of society. Treat librarians with respect and don't objectify, unless consented too ....