The crew already had 2 overnight flights before could be fatigue and simple mistakes during bad weather.
That sleep loss contributes to accidents and is therefore relevant to the discussion (if true) is in no way speculative: https://www.ncbi.nlm.nih.gov/pubmed/?term=accident+sleep+los...
Discussion of specific issues is interesting, but they're better discussed in extra threads instead of as speculations on a case nothing concrete is known about.
This specific subthread starts with either speculation or unsourced claims of lack of sleep: That alone is an interesting topic of discussion, but better placed on a submission about a specific case where this is known to have been a factor, or some general article about it, not here.
Exactly - the idea that the crew had any sleep loss is speculative. I doubt anyone would suggest that lack of sleep doesn't contribute to accidents.
I don't think it's too different from reading a story about a murder investigation and idling throwing out 'could be Bob that did it - I hear he gets angry sometimes' without knowing Bob, knowing whether he usually gets angry or not, whether or not he was angry or not at the time, or whether anyone was angry at all in the situation or even if Bob had anything to do with it in the slightest.
And the requirements are different between passenger and cargo operators.