Airbus documentation is simply false.
Originally Posted by Third Interim Report P20
If the CAS measurements for the three ADR are lower than 60 kt, the angle of attack values of the three ADR are invalid (NCD status) and the stall warning is then inoperative. This results from a logic stating that the airflow must be sufficient to ensure a valid measurement by the angle of attack sensors, especially to prevent spurious warnings on the ground.
What a ridiculous pseudo reason really !
Those AoA vanes move at nothing. I took the opportunity to manipulate them the other day and 15kt of relative wind is probably already in excess to place them in the wind on. No wind on them, they also stay in the position you place them, like absolutely not affected by gravity.