Well put, tilii.
At present, CAP371 is the law, supported by the ANO.
The argument here is not whether this or that rostering pattern is legal or not if one ignores the fatigue catch-all paragraphs, but whether it is safe. If it is not safe, then the law needs to be changed.
And whether or not changed, the law needs some form of enforcement that actually works, so that crews do NOT fly when fatigued, and are not rostered for fatiguing duties because the airlines need to get their money's worth out of their staff. My contention is that the current system of enforcement does not work.