Is there a reason that a pilot in a commercial airliner should be allowed to put that kind of stress on the airframe? Is there any real-world example where that level of control has saved people from crashing?

If the controls of Air France 447 had force feedback controls like in Boeing (where the control stick would have shaken and have been physically moved) it would have been obvious to both pilots (not just the one pulling the nose up) that the airplane was stalled, nose up. Further more if it had been a Boeing, that stick would have been shaking indicating stall warning. Because the airbus was fly by wire side stick, the 2nd pilot could not physically feel the pilot-in-charge had pulled the stick hard astern, keeping the nose up.

Autopilot correction in either case would not have done anything since the whole reason the plane in that case was out of autopilot was because the autopilot was receiving conflicting sensor readings and needed a human to determine which to trust.