Captain Beatty describes the slow process that led the people of his society to be so close-minded, calloused, and shallow. He describes how people became too busy and lazy to read, too involved in the immediate to want to stop and think about life, or the deeper meaning of existence. As a result, books faded into non-existence. Government helped the process along, because thinkers cause problems and revolution. The other issue was political correctness; societies are so intent on not offending anyone that everything becomes edited and bland. The government took this and ran with it too, because "we can't have our minorities upset and stirred...People want to be happy". Those that do have opposing viewpoints are shut down, like Clarisse and her family.
The bottom line is that in Montag's society, the powers that be are touting great freedom, great fun, great busyness, and taking care of the people, when in reality they are limiting their freedom by editing and filtering truth. People are spoon-fed what they are to believe, through mass media, and eventually just stop thinking for themselves altogether. Truth is what the media tells them it is. Bradbury seems to be stating that the greatest enemy to freedom and truth is our own laziness and lack of desire to work and think, which is manipulated by powerful leaders and governments that use the media to promote messages that keep them in power.