Why the hell did the stupid automation silence the stall horn ?
A great question. The systems silenced it because the IAS fell below 60 kts for a time. This caused the FWC (Flight Warning Computer) to silence the STALL warning.
It should be that any time stall AoA is sensed with the aircraft in the air mode that the stall warning sounds. Airbus must have assumed that if the IAS is < 60 kts then the aircraft is on the ground even if the weight on wheels switches say it is in the air. There is no logical explanation for it silencing the stall warning based apparently on IAS alone.
I'd love to know why display of AoA on the PFD is a very expensive paid-for option. IMHO knowing the AoA is at least as important as knowing IAS, if not more so, and should be a mandatory instrument/display.