Not only is that Filoni’s interpretation not Lucas’ but Vader’s fate being based on a duel he wasn’t in when he was 9 and implying his turn is the Jedi’s fault is so fucking stupid.
We were told Vader was seduced to the dark side, not that he was a poor baby victim of bad Jedi teachings.
We were also told the Jedi were in their prime before the Empire.
It’s like blaming Walter White becoming Heisenberg on Hank.