1994 was not some ancient period of your so-called "myths" about ST, otherwise, the same book's chapter about other possible Enterprise captains (Jack Lord and Lloyd Bridges among them) should be disregarded as myth in the present day...despite the fact they were documented considerations still accepted as fact.
CBS and Paramount continue to propagate myths about the series in promotional materials. Just take a look at a book like Star Trek 365
(2010). It's a nicely illustrated book, with some good material in it, but that doesn't stop it from simply quoting Roddenberry's debunked accounts of certain things (i.e. Number One's elimination from the first pilot).
I don't get your second point. Because the book has things in it that aren't true (like the demographic story) it can't have things in it that are true (like Jack Lord and Lloyd Bridges being considered for the role of Robert April/Christopher Pike)? That doesn't make any sense.