Beatty, ironically a well-read man, explains to Montag that censorship happened because the people allowed it. They wanted to be happy and not disturb their thoughts with things that were controversial. If you want a man happy, you don't give him two sides of an issue to confuse him. The larger the population, the more minorities, the more people to insult and upset, the more ideas to deal with, which creates unhappiness. He tells Montag,
"The bigger your market, Montag, the less you handle controversy, remember that! All the minor minor minorities with their navels to be kept clean. Authors, full of evil thoughts. lock up your typewriters. They did. Magazines became a nice blend of vanilla tapioca. Books, so the damned snobbish critics said, were dishwater. No wonder books stopped selling, the critics said." (pg 57)
Beatty explains that the censorship did not come from the government, it came from the people. People stopped reading so that things could be done faster and make people happier. The people didn't want to have thoughts introduced to them that might upset their happy nature. The people chose the censorship, not the government. He says,
"It didn't come from the Government down. There was no dictum, no declaration, no censorship, to start with, no! Technology, mass exploration, and minority pressure carried the trick, thank God. Today, thanks to them, you can stay happy all the time..." (pg 58)
The people also ensured that censorship continued. They reported their neighbors for having books and reading. When they came to burn Montag's house, Beatty admitted that not only did Mildred, his own wife, turn in Montag for his books, but his neighbors also had reported him.
Faber also admits his role in helping the government enact censorship. It couldn't have happened without the role of the people. Faber says,
"I saw the way things were going, a long time back. I said nothing. I'm one of the innocents who could have spoken up and out when no one would listen to the 'guilty', but I did not speak out and became guilty myself." (pg 82)
He was a coward and did not speak up at the time when books and reading were being criticized. He is just as guilty as those who promoted the idea. Censorship came about because people wanted things done faster, they didn't want ideas challenged, they didn't want criticism, and they didn't speak out when they saw censorship happening. Montag feels empty inside because has become a product of this society, feeling the way they tell him to feel, thinking what they tell him to think. He feels empty inside. Faber tells him,
"It's not books you need, it's some of the things that once were in books." (pg 82)
At the end of the book, the men have memorized portions of books or whole books. They intend to pass these down through generations. They intend to hold these books precious in their minds until THE PEOPLE want to know about them again. This reinforces the idea that censorship comes from the people. At the end, Montag thinks,
"To everything there is a season. Yes. A time to break down, and a time to build up. Yes. A time to keep silence, and a time to speak." (pg 165)
To help you with your essay, you might want to check out the historical content and critical overview listed below that you can find on enotes. It gives a lot of background on what was going on at the time Bradbury wrote this book.