When I was working in engineering in the transport industry, we always looked for the "root cause" of failure of a component or system. This took some weeks in fact to solve some of the more complicated faults, so what is the "root" cause here, I would say without a doubt the wrong fuel was loaded, without that, all the other factors, ie: tired pilot, long trip, etc etc are irrelevant. As no accident would have occurred.
This is based on the headline cause for the crash and nothing else...