Ok so first someone wrote a book and someone else reviewed it: this:
This made some Rabbis angry.
Then people complained about it
I admit I have not read "Torah From Heaven: A Reconstruction of Faith". I saw it on the bookshelf took a look at it and said "This is Louis Jacobs/Heschel/et al" and put it back. [These approaches, are silly in my opinion, because once you've knocked out the direct link between God and Torah through Moses you're stuck with a very fluffy wishy washy sortav "well God inspires people and thats cool, and maybe he inspired people to write cool things", but that's a topic for another time]
If the review is accurate, it confirms my assumptions.
So some thoughts. Firstly the Va'ad HaRabonim is right that that's what Orthodoxy believes
however they are wrong because Orthodoxy is wrong about history etc.
DovBear IMHO is just nitpicking. Ibn Ezra gives a grand total of 12 verses (and maybe a scattered few here and there) to Joshua. But he was not a Bible critic and no traditional commentator was a Bible critic. Bible criticism was never accepted by Orthodoxy not in the past and not now. (And yeah some people, like James Kugel, call themselves Orthodox and accept Bible criticism but I think that's basically just Conservatism, a rose by any other name...)
Technically DovBear is right. Traditional commentators have said not every single last word was literally written by Moses. But once again, very few words, and very few commentators are included in this. The Va'ad HaRabonim did express the most extreme version of TMS i.e. its all from Moses down to every single letter, but they're just parroting the Rambam's principles of faith. And lots of people believe that those are Halakhically binding (that's what the Rambam wanted!)
Honestly, let's put things in context, the offensive book in question is not the Ibn Ezra and it's not saying "btw a few verses here and there maybe were written by Joshua." No. It's saying according to the review:
Rabbi Solomon argues further that historical scholarship makes it impossible to believe that Moses was the author of Genesis to Deuteronomy, or that our text of the Torah today is identical to the original one.
There is a big difference between saying Joshua might have wrote 12 psukim according to one medieval commentator and saying "historical scholarship" rules out Mosaic authorship for entire books of the Torah. Therefore I'm not vaguely surprised that the Va'ad HaRabonim said this and I don't know why we should expect otherwise. They're just saying "this book is nice, but a reminder most Orthodox Jews don't believe this". Quoting Ibn Ezra is missing the main point of the message which is an affirmation of the connection between the man Moses and the writing of the Torah.
I would rather focus not on why the Va'ad HaRabonim are "wrong" according to Orthodox Judaism (cuz I think they sum up pretty well what most Orthodox Jews think and have thought in the past) but rather focus on why they're wrong according to logic. And the answer is: "because historical scholarship [and common sense!] makes it impossible to believe that Moses was the author of Genesis to Deuteronomy".