Exactly. If I'm gonna buy an official Trek history, I expect it to be true to that history. The minute you start saying, "Well that bit of Trek doesn't count" (in this case, the entire first three seasons and first 2 episodes of the fourth season of Enterprise!), you're very much NOT being true to canon Trek. It's a variation of the old "Enterprise is an alternate universe blah blah" thing.
The novels do a masterful job of making it seem as though everything in TV/film Trek "happened" They tie it all together and for the most part hide the seams really well. If this project can't do the same, I might as well read these fan manuals instead
, which essentially are the same but ignore the entirety of Enterprise and use a mishmash pre-TOS history from the old Spaceflight Chronology and old Treknical fanzines instead.
Of course, I may be overreacting somewhat. Hopefully he just meant that the TCW wouldn't have been common knowledge, or known to the books' in-universe writer, or something.