This is at the beginning of Part III of Fahrenheit 451, "Burning Bright." Beatty is talking about the mystery and mythology of fire. Some say the discovery of fire is the beginning of technology. Fire has been used to power machines but it has also been a destructive force. Of the many applications of fire, Beatty is celebrating the power of fire to destroy responsibilities and consequences.
If ideas and philosophies in literature complicate life, Beatty would have them burnt. If the public is kept in the dark, kept from ever reading challenging ideas, they will stay passive. But as soon as the public is given access to knowledge and encouraged to learn, they will develop a desire for more knowledge and will want to be a part of making decisions that affect themselves and the society they live in. Taking part in those decisions, they will want to become responsible and they will want to face the consequences for their decisions. In short, a literate, free-thinking public will embrace responsibility.
Beatty admires the "beauty" of fire to destroy all literature that would encourage the public to think for themselves. For Beatty, the beauty of fire is that by destroying literature, people become passive and mentally suppressed.
Beatty also implies that people should be "burnt" or done away with if they, like literature, encourage others to think for themselves. In this same paragraph, Beatty says:
A problem gets too burdensome, then into the furnace with it. Now, Montag, you're a burden. And fire will lift you off my shoulders, clean, quick, sure; nothing to rot later. Anti-biotic, aesthetic, practical.