Scimitar. having done the training captain but for circa ten years, I understand how you feel.
However, my take on this is that, in terms of promotion to command, we know that even your best prospect might make a mistake since he/she is only human and the system will never be perfect. But if they do screw up, at least you can put hand on heart and say you did everything possible to ensure it would not happen.
Unlike the case where one might be tempted to let a "marginal" candidate through in which case you would never forgive yourself if anything went wrong.
In psychological terms there is a difference, of course, between one's "espoused theory" - what you SAY you would do in a specific situation and one's "theory in use" - what you ACTUALLY do when faced with the same situation. As human beings we get round this paradox by "rationalising" - "Ah well, I did it that way because....etc".
That is precisely what is happening on this thread, I venture to suggest. We are all SAYING well if it had been me I would have done so and so but you don't know what you might have ACTUALLY done until you are there!
In training we attempt to circumnavigate (no pun intended) this by actually placing pilots in the sim to see what they ACTUALLY do and then we can discuss and debrief etc and run the scenario again with, perhaps, a different outcome.
Problem is that in the "real" world we often only get one shot at it and hindsight is a great thing. All we can do when "it" happens is to try and learn from "it" to prevent future occurences. It is perhaps ironic that this accident happened to one of the most professional and safety conscious airlines in the world but as my son keeps telling me, sometime "s**t happens"!