Nomorecatering, what you say is true - up to a point.
The truth is that DJ exercised poor judgement that night. No one disputes that, including DJ himself.
Equally however, the environment is designed to have multiple lines of defence. The PIC is always the last line of defence as you make clear. But hopefully the PIC is flying for a safe operator, and that operator is kept safe by appropriate regulatory oversight.
Unfortunately these "earlier" lines of defence both failed, leaving DJ horribly exposed to bad judgement and bad luck. The operator and regulator also contributed to the outcome that night. Unlike DJ however, then have sought to minimise their hand in this. And it is disturbing to many that the purported independent investigator seems complicit in this.
FYI, Noumea wasn't an option that night. The operator had been barred from New Caledonia for the previous 12 months because the plane was not fitted with latest generation TCAS as required under French (EU) regulations. So the only ILS runway in that part of the world was off limits. Ironically the operator had just finished putting TCAS into the aircraft, but the pilots had allegedly not been trained in its operation.
Similarly they didn't have RVSM. It has been speculated the reason why full fuel was not uplifted at Apia was the requirement to climb above RVSM airspace upon departure.
Thats how marginal the whole thing was.