The systems only imposed the 13 degree up angle because the pilot asked for it by backwards pressure on the SS that increased the pitch angle to the point where the aircraft stalled - the system was doing exactly what the pilot requested.
That might be how the system is designed to work but is it how a human "naturally" expects a system to work? Hasn't it been proven over the years that in an emergency we revert to how we expect things to work regardless of how they actually work or how we're trained to use them?
If I turn the thermostat up on my heating system I wouldn't expect the temperature to get hottor and hotter indefinitely.
If I turn the steering wheel of my car I wouldn't expect the turn to get tighter and tighter until the steering rack is on full lock.
Even the accelerator pedal on my car mostly behaves like a speed control rather than an accelerator. Once I have reached the desired speed I don't lift off the pedal to maintain that speed. I have to keep it pressed.
What other familiar systems have a "runaway" behavior like the auto trim?