Elsewhere on this forum there is a thread about whether or not airlines can and should take action over crews with alcohol problems. Neither they nor the authorities are yet prepared to take action over fatigue.
Here we have (circumstantial) evidence of a crew making mistakes when fatigued, yet the problem is still not addressed directly.
When (not "if") we have an accident, the error will be put down to the crews. There has been study after study that firmly stated that pilots are flying fatigued and making errors of judgement or errors in operation of the equipment. And yet the fundamental reason for those errors is not corrected. And why not? Because a safer system will cost the airlines money.
N.B. The opinions expressed in this post are mine, and do not (necessarily) represent the view of PPRuNe management.