Esoteric Freemasonry 

That part of Freemasonry that is for only those who are initiated into the Mysteries of Freemasonry.

This information only makes sense if you are a Freemason so there is not reason to give it to others who are Ignorant of the Freemasonry.  As it makes no sense for a theoretical physicist to attempt to explain theoretical physics to those ignorant of theoretical physics it makes no sense for a Freemason to attempt to explain Freemasonry to those who are ignorant about Freemasonry.  Anyone interested in theoretical physics can study the topic to become a theoretical physicist and those who want to know about Freemasonry can join Freemasonry and become Freemasons so that they can understand Freemasonry.  Most people are too lazy to do either.

Information that is given to the public is called Exoteric Freemasonry.