Surely in a spiral dive you would have increasing G if you pulled backstick which you could sense. Can't see the confusion myself, certainly not for 4 min's.
Certainly one would think so.
In this case we see that Attitude+Power was not obtaining the Performance one would normally expect.
The crew seem not to have realised they were in the stall regime while all us of in our armchairs are at a loss to understand why they did not.
I have seen somebody in a steam gauge sim with white on black AH invert the ac at 16000' and fail to realise what he had done until after he "hit" the ground. Fixation can take over, and deafen you to the guy yelling "roll left" directly in your right ear.
Here it seems the entire crew were aware they were on the way down without knowing why or anybody offering any ideas on how to change the situation for the better.