This usage of "banned" has been around for over a century, beginning in the USA when the USPS tried to interdict copies of Joyce's Ulysses. It further gained popularity when Tropic of Cancer and Lady Chatterly's Lover were challenged as obscenity in landmark 1950s-60s trials.

The first Banned Books Week happened in 1982, sponsored by the American Library Association.

However, yes, since 2021 there has been a big spike in the usage of the term "banned" books. Perhaps it was because around that time, there has been a massive push to challenge books (the ironically named "Moms for Liberty" though whose liberty they are protecting seems to be up for debate). 2023 saw >4,000 books challenged, whereas an average year between 2001-2020 saw ~275.

Perhaps if people stopped trying to police the reading habits of others' children, people would be less apt to talk about so called "banned" books?

I, for one, think that policing the reading habits of other people, and the micromanagement of libraries, is far more odious than the hyperbolic use of the word "banned." No one has to check out a book they don't want to.