Why does Beatty say their society agreed to start burning books?

Answer: To Maintain Social Order

Explanation:

In the novel "Fahrenheit 451" by Ray Bradbury, Captain Beatty leads the Firemen who are a government arm tasked with the destruction of any and all books by burning.

Captain Beatty while explaining the reason that books were to be burnt to Montag, explained that the main purpose was to maintain the social order.

He said that society had gotten so overpopulated and sensitive that they just did not want to offend minorities. He said that books seemed to always annoy at least 1 minority, for example books aboit lung cancer being insulting to Cigarette smokers.

There was also the explanation that it was done to give everyone equal intelligence. It was said that books made people read and become smarter than others so it was believed that if no one read then everyone will be of equal intelligence.

So the government outlawed all books to keep the population happy and to maintain social order.