Supporting data, studies?
Additionally, you appear to look at a few data points and draw quick conclusions without understanding the rest of the data and history of the operations.
Think most professional aviators simply are more nuanced and patient at looking at the causal factors and letting the investigation continue to look at all the data in a balanced view to prevent a future accident. In my experience, fatigue isn't a snapshot of a few days, but a continuum over a long period of time and factors.
Integral, not a snapshot. Likewise training and operational performance.
SD