I think the journalist rule is good for books that go deep into a topic, like many of the ones you've cited here. On the other hand, I would expand your caveat

I think the journalist rule is good for books that go deep into a topic, like many of the ones you've cited here. On the other hand, I would expand your caveat around biographies to say that journalists are generally very good when it comes to writing about events. Barbarians at the Gate is a good example of this - it required authors who were able to dig deep into _what_ happened. There's obviously some info on why things happened there as well, but the primary purpose of the book is to inform the reader of what occurred, which is a good use of the journalistic skill set.