According to Captain Beatty, how did censorship begin?

Montag is so affected by the woman who chose to burn with her books that he decides to skip work, effectively intending to call in sick. He has also stolen a book from the woman's house. When Montag does not report for work, Beatty goes to visit "the sick man." Beatty goes into the history of the firemen and how censorship began: 

Every fireman, sooner or later, hits this. They only need understanding, to know how the wheels run. Need to know the history of our profession. 

Beatty says it all started with the Civil War, presumably indicating it started with a rift between culture and race. Beatty says people did not get along until photography, film, television, and radio became popular. These mediums were effective in keeping people happy because they applied to a mass audience. Beatty goes on to describe how fast-paced this kind of entertainment was becoming: 

School is shortened, discipline relaxed, philosophies, histories, languages dropped, English and spelling gradually neglected, finally almost completely ignored. Life is immediate, the job counts, pleasure lies all about after work. Why learn anything save pressing buttons, pulling switches, fitting nuts and bolts? 

In other words, with this kind of entertainment and lifestyle, there are less reasons for the public to think for themselves. Books were too particular, profound, and diverse whereas movies and television were simplified and could appeal to the majority. Therefore, Beatty claims, it was the public (not the government) that dictated the censorship of books. The public would rather be happy with a homogeneous, generally well-liked product than have to deal with many different philosophies and viewpoints in books:

There you have it, Montag. It didn't come from the Government down. There was no dictum, no declaration, no censorship, to start with, no! 

Beatty goes on to say that the firemen were simply carrying out the will of the people. People don't want to be unhappy or offended. So, literature would be banned and the mass appeal of the movies and television (parlour shows) would be embraced: 

Colored people don't like Little Black Sambo. Burn it. White people don't feel good about Uncle Tom's Cabin. Burn it.