Airplanes coast down fine after a (double) engine failure, but they don't coast nicely when your primary instruments aren't working. The Air France flight didn't just loose airspeed indication, they got invalid readings and all associated warnings. Unfortunately that is the common failure mode for flight instruments, they don't just show nothing, they show wrong values. Fortunately pilots are trained to know how instruments work on the inside and what the most likely wrong indications and their causes are.
The problem the author points out is that you cannot "pause" to think about what information may be correct and which instruments to follow. You have to react immediately, which is much harder than considering the same decisions sitting at a desk reading the NTSB report.
If the low speed indication/alert is correct you need to push the nose forward immediately to keep the aircraft out of a stall, if the high speed indication/alert is correct you need to pull power to flight-idle and nose up carefully but immediately to avoid overspeeding the aircraft and risk structural failure.
AFAIK the Air France flight would have been ok if they had not even touched the controls. They had a lot of altitude. Of course easy to say from the arm chair.
I'm not sure how easily a regular airline overspeeds or stalls if the controls are close to a middle position. They should be aerodynamically stable (if loaded correctly).
They were initially close to a high altitude stall, the margins are not that large at that altitude, so just dropping everything isn't really an option.
The report highlighted training, which I guess is always possible to point out, but looking at the event I think they could have made more conclusions regarding how the control system performed counterintuitive by emitting stall warnings at the time they actually did the right thing, and provides little feedback when it drops into alternate law making a standard full pullback into a potentially dangerous move.
What I remember reading of the Air France flight was that both people flying understood perfectly well the situation, and had plenty of time to get out of it, but one panicked and tried to pull up even though that was exactly the wrong thing to do. The other problem was that no one else realised that one of them was trying to pull up and the plane averaged the actions of the two sticks (pull up and dive) causing effectively zero net action. (Other planes feedback each stick's action to the other so the other person would soon have realised what was going on.) They had so long to fix the problem that the captain (who had been sleeping) had time to wake up and enter the cockpit, and he finally managed to coax out the information that one of the copilots was trying to pull up, and for them to stop. By that point they were only seconds from the water and it actually was too late.
The problem the author points out is that you cannot "pause" to think about what information may be correct and which instruments to follow. You have to react immediately, which is much harder than considering the same decisions sitting at a desk reading the NTSB report.
If the low speed indication/alert is correct you need to push the nose forward immediately to keep the aircraft out of a stall, if the high speed indication/alert is correct you need to pull power to flight-idle and nose up carefully but immediately to avoid overspeeding the aircraft and risk structural failure.