His glider experience didn't helped with the stall of a swept wing, at cruise altitude.
The stall warning was not triggered continuously during the stalled condition, but it was triggered when not suppose to. I believe this aspect was never discussed.
On the A330 as on other aeroplanes of the same generation, the threshold of the stall warning varies with the Mach, in such a way that it is triggered - in alternate or direct law – before the appearance of buffet.
The stall warning was triggered at 2 h 10 min 51, 10 seconds later the variometer indicated a solid climb of 2000 ft/min and the vertical acceleration was around 1g. In less than a minute, the aircraft vertical speed exceeded -15000 ft/min with associated aerodynamic noise of the increased airspeed (in wrong direction).
Now, the conventional stall of a glider: almost zero aerodynamic noise, clear buffet, 0 g, the natural drop of the nose, the aerodynamic noise rapidly increased. An experienced glider pilot estimates the speed by aerodynamic noise.
https://youtu.be/7QpUj7wiPDI
Well Bonin never recovered from his steep dive.