Because she wrote it very well
Fahrenheit 451 is set in an unspecified city at an unspecified time in the future after the year 1960. The novel is divided into three parts: "The Hearth and the Salamander", "The Sieve and the Sand", and "Burning Bright".
Slave owners thought of slaves as equipment they took care of them but showed no compassion and when the “equipment” didn’t work it was there fault and not the owners