I expected to put to rest some or most of the more disconcerting possibilities once the prelim was released, but if anything I'm now even more astonished after digesting it for a few days! Like a good mystery this one just keeps getting stranger and stranger -- putting aside the tragic loss of life of course.
And I will respectfully disagree with some comments that there surely must have been fumes or some other debilitating circumstance affecting cognitive function. Indeed, it's more than possible the cockpit crew were incapacitated to some degree, but in my travels through several serious, non-aviation incidents I've seen multiple instances of perfectly capable individuals acting in the most peculiar ways when under stress while the bucket is full. Some of the most competent people engaging in their fields of expertise can go completely off the rails under the right stimulus. We've all seen such behavior described here at this site many, many times unfortunately.
It's just my own hunch from the start, but I think I already know why so many mistakes were made (as do most here methinks) and I shall keep such speculation to myself -- for now. My previous attempts to "sum it up" were quite rightly removed and I'd like to avoid adding to my shockingly poor track record for moderated commentary!
Happy vapour trails to you all.
Edited for spelling. The artificial incompetence on my phone keeps changing perfectly good English into gibberish.