The aircrew will inevitably and correctly be blamed for this accident - had they lived, they would almost certainly now be facing manslaughter charges. But blaming the crew won't stop a recurrence. The appropriate legislation is already in place - the approach ban would surely have prevented this, had the crew not deliberately ignored it, not once, but 3 times.
It also appears the AOC holder failed to properly supervise & monitor the crew, and that the regulator failed to properly supervise & monitor the AOC. I note that these issues are specifically named as being part of the focus of the continuing investigation.
What about those responsible for the airspace in which the aircraft is flying? Should controllers be 'whistle-blowers' when they have good reason to suspect the rules are being broken?
I have no doubt whatsoever that the vast majority of commercial pilots are thoroughly professional & would never attempt a Cat1 approach in the accident Wx. I also have no doubt that any decent airline would take extremely strong action against any crew if they ever attempted to do so.
However, in the final analysis, rules & regulations will not adequately protect the public unless they are effectively enforced - and I am not convinced that, at the present time, that enforcement is sufficiently effective.