I counter: it should be okay for anyone to retroactively edit books. The problem here is not that the books are being made worse, but that the copyright holders are the ones doing it, they’re the only ones who can legally publish the book, and thus as used copies deteriorate and disappear, the only legally published editions available will be the censored versions.

The harm comes when the original work stops being sold to force new buyers to only ever have access to the rewrite.