That is exactly the point, it does matter how much fuel you have on board, you cannot take the law into your own hands unless your justification is absolutely watertight.
As I said before, all they had on board other than FR was "approach fuel". They did not have any "flight fuel" as they could not fly anywhere else.
So do they doodle around in the clear blue sky above ever increasing fog and get to a point where they have used their "approach fuel" to conduct an approach with no prospect of a missed approach or use what approach fuel they had and conduct an approach knowing full well that they have the fuel have a go at a second approach.
The CARs allow a pilot to "
pay due regard to all dangers to navigation .. and to any special circumstances which may render a departure from those rules necessary in order to avoid immediate danger"
Say after me, " if I deliberately break the rules, I will have a watertight reason."
They did and I did. Somewhat similar circumstances, but I had the luxury of diverting from a fogged in aerodrome to a CAVOK aerodrome, but I used 2/3 of my FR to get there.
And it was not a bugsmasher.