(except in so much that the DH on a CAT 1 approach could well be the limiting factor).
Anyway I appreciate, that you, at least partly agree that ceiling
is not totally irrelevant in this case.
The required visual reference means that section of the visual aids or of the approach area which should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position, in relation to the desired flight path.
Looking at the result, the pilot obviously didn't have the "required visual reference"
at the Decision Point at Decision Height.