IMHO, and FWIW, I lay the blame for the crash into the sea on the shoulders of the pilot, for not doing the correct stall recovery drill, i.e. unload or drop the nose to recover the airspeed and at 30'000 ft, hang the altitude loss. The fact that the aircraft was descending rapidly is not a valid reason to pull back on the side stick.
The reason for the stall I lay squarely on the shoulders of Airbus/Air France for not fixing the pitot problem years earlier.