I don't think anyone is saying that. People are rolling their eyes because these lists are inevitably comprised of extremely popular books that were once, usual

I don't think anyone is saying that. People are rolling their eyes because these lists are inevitably comprised of extremely popular books that were once, usually temporarily, removed from a single school library somewhere in the US. There are books these libraries cannot even buy and which the school librarians will often not buy or even destroy for ideological reasons, but these books do not appear on these lists. Only the popular, famous, and widely available books that are often on required reading lists. EDIT: A great example is To Kill A Mockingbird, which always appears on these lists. TKAM was once 'banned' because people considered it too antiracist, now it is often 'banned' (rare isolated instances in either case) because it contains racial slurs. Nevertheless for the past 20 years almost every American schoolchild has been required to read TKAM. It is absolutely absurd to speak of it in any meaningful sense as a banned book. It's just a book librarians and teachers love that sometimes gets complaints.