Why was this book censored and banned and why was this wrong to do?

Fahrenheit 451 by Ray Bradbury tells the story of a society in the future in which all books are banned and firemen are employed to seek out books and burn them. The novel is a warning against banning and censoring books, so it is ironic that this book itself should be banned in certain schools and communities, but this was indeed the case.
Some schools in conservative communities banned Fahrenheit 451 for having "obscene" words such as "hell" and "damn" in it. Parents also objected to certain actions that the characters perform such as smoking cigarettes, drinking alcohol, and committing violence. One school allowed the book to be read by students, but censored it by blacking out all words considered vulgar or unacceptable. Other parents objected to the portrayal of Christians in the book and the fact that a Bible is burned.
It is wrong to ban or censor Fahrenheit 451 because its theme of the importance of books as a means of free expression is so important. When Bradbury wrote the book, historical events such as the book burning by the Nazis, Joseph Stalin's repression of free thought, and Joseph McCarthy's persecution of creative artists had been in the news. Bradbury emphasized the dangers of such repression and the importance of intellectual freedom.
http://web.archive.org/web/20030813004557/www.banned-books.com/bbarticle-miss.html

https://www.chron.com/neighborhood/article/Parent-criticizes-book-Fahrenheit-451-9636755.php