why do journalists and authors often put brackets around words in seemingly strange parts of sentences?

Question

For example, a sentence I just read went as follows:

> “‘I don’t think [the book] had anything to do with his arrest and neither does Anne Marie Schubert,’ he says.”—(Excerpt from the appendix of ‘I’ll Be Gone in the Dark’ by Michelle McNamara)

Found in Other.

Answer 1

If the sentence would be hard to understand exactly as written or said, the brackets indicate that a substitution has been made.

“He said that it was a crime against humanity” would be obscure if you didn’t know that the antecedent of ‘it’ was putting ketchup on hot dogs.

“He said that [putting ketchup on hot dogs] was a crime against humanity.”