We don't know what they knew. They're dead, and we can't interview them. We can only guess.
I set aside the root cause in the first few paragraphs, and explicitly said I don't take issue with that.
I take issue with a particular set of descriptions. They are not germane to the cause of the crash, but they are relevant if you care what the true story was. The errors in the CAB and ALPA reports are egregious and obvious. "Slapdash" is an appropriate term.
I don't accept that they are beyond question merely because the writers are probably now dead.