From: Steve Shaw - PM
Date: 28 Nov 17 - 07:56 AM
We need to know, and have the right to know, the bad things that experts are predicting. We don't pay these bastards to keep embarrassing information from us. Let's take back control!

I don't think there was ever the intention of giving you the details. Parliament may have a 'right to know'.
David Davis does not even seem to trust the Brexit Committee:

Davis said he was withholding the information because he had "received no assurances from the [Brexit] committee regarding how any information passed will be used".

Of course, if the Committee had given assurances that the details wouldn't be shared with the media, or with the EU, maybe they'd have got the full details.