And honestly, there *should* be an equivalent of §230 for the bookselling industry, just like there should be a federal antiSLAPP law. But that example you keep using of bookselling actually is a good example of why §230 doesn't work the way you think it does!

S230 works by immunizing cases even when the scienter requirement applies (which is the 1A standard). That means, even if a plaintiff pleads “info and belief” that the platform knew content was defamatory, the platform still wins on a MTD, when it would go to discovery and summary judgement under 1A

Because there should be an equivalent of §230 simply for *selling* the book, because that's an action that doesn't contribute to the development of the allegedly defamatory content, but if there were, the *publisher* of the book still wouldn't be protected by the liability shield.