This accident makes no sense if you just look at the pilots actions during the final stage of the landing.There must have been a reason why he ignored warnings and operated so far outside the envelope.
The fact that he operated so far outside the envelope is the reason he must be sent to jail.
I am sure there are many reasons for this behaviour and clearly there are faults with the system, but his behaviour in the final stages of the flight are completely unacceptable.
He didnt just break a couple of rules, his behaviour was grossly negligent and directly caused the deaths of 21 human beings.