The cause distilled
At the risk of being accused of harping on about professionalism (or the lack of) and over simplifying the analysis of the accident you need only look at the writing between the lines in the "Celebrate the professional pilot" thread, now closed.
Of over 2000 views only one pilot had the testicular fortitude to admit that he was coerced into "non compliance". Even on this forum that thrives on anonymity, nobody else could put their hand up and say that they had stood up to coercion from their employer. Either too afraid speak up or just plain had never exercised command judgement. Hopefully it is not the latter.
Combine that GA upbringing and an organisation culture where blind obedience to a figure that had and exercised the power to make or break a career then you set the stage for this sort of accident. You only have to wait for the players to walk on stage.
Even worse you condition the pilots to replicate the same behavior in the cockpit.