Here's a pointer towards a possible true root cause:
If the crew were told on that day to miss TOD significantly and then either push the cat back into the bag, land inside the stable approach criteria - or failing that abandon the approach at a responsible and proffesional moment - would they had been able to?
Yes, they would. Although on their own they did not.
It's not the lack of skill, or insufficient knowledge of the regulations that killed that day but improper conduct and derelict of duties.
Why that happens is the life saving question. Similar to the NDB RYR at Bergerac dissused in the next thread.
One more thought: A man does not usually choose to make a grave mistake.