Very informative thread.
I think the psychological key might be the PNF's statement at 2:10:17 "we've lost the the speeds..." which implies he thinks the failure is more than one, and communicates that to the PF. With such extreme values when they are all working its easy to understand why they might be sceptical of what they were reading. Unfortunately we will never know for sure because we don't know what the PF was seeing.
Also at 2:10:22 the PNF just says "Alternate law protections" to the PF without specifying which. This seems a recipe for pilot confusion, particularly in such a stressful situation when the ECAM hasn't said why the ap has disconnected and control switched to alt2. Again psychologically, if you have different states, far better to have different names for them to avoid exactly this sort of potential misunderstanding which is the last thing you need in a time critical environment.