Beatty's love of fire is a self-contradiction. As a fireman who seems to enjoy the burning, he also has a great appreciation of literature which means he must be a learned man who has read many books.
For me, Beatty is a sad figure who has embraced his current circumstances with a vacant disbelief, accepting that this is the way it is in the world, giving up hope that the joy of knowledge and books is gone forever. In my view, he is a lonely man who functions like the mechanical dogs in the story.
His depression and sadness is brought to a climax when he does not attempt to protect himself from death. He wants to die, he doesn't care about this life anymore.
"It is Beatty who explains the history of firefighting in the story and who fully embraces its justification, ironically quoting from literature to support his arguments."
Beatty fits into the symbolic message that fire represents in this society, as both a destructive force and a cleansing mechanism. Fire purifies through its destruction and for Beatty, destroying the old way of life, burning the books, is cathartic, because why have the books if they cannot be read and enjoyed.
Knowledge is being burned from the minds of people as a mechanism to control behavior. Censorship by fire, very effective, there is nothing but ashes left. Symbolically, the minds of this society are being gutted the same way that books are being burned, the knowledge is removed, destroyed so that it can be replaced with images and commands that control the individual.
There is no individual thought, books are a danger, the sooner they are gone, the less chance there is for revolt around the remnants of a lost society.