If you are going to write factually incorrect stuff then remember the saying about it better people thinking you are a fool........
And the fool would be? The one who omits QF diverted ahead of VA and landed at Mildura safely, or that the diversion was flawed because updated information was not sought prior to diversion or not passed on when alerted by aircraft arriving earlier. For instance not much made of the Rex flight who saw the unfolding drama and immediately diverted to an alternate to avoid what was a growing list of unknowns ahead regarding holding aircraft, unforecast weather, etc, possibly causing them issues. Or should I recite the CARs which require a PIC of RPT/Charter to be familiar with all airports, including alternates and weather patterns on the route to be flown, so that diversions and such can be made without having to fly to 'unfamiliar' airports. I mean seriously the amount quoting Perth is so isolated means a captain operating there should be aware of all alternates en-route and in the area and it would be easy to be familiar as there are not that many, and due diligence means you must be familiar with all alternates and emergency possibles. Some here make it sound like the QF crew are barely trained and experienced and are flying a Cessna 172 on a private hop.
PS Mia forecast had a Tempo for broken low cloud before the VA aircraft had even diverted, so they needed to arrive at MIA with at least 60 minutes holding, so it was a marginal destination as is.
Point still stands though, that if every other port in the area had alternate or marginal forecasts, why was the aircraft operating on bare minimum fuel.
One last clear point; what the QF crew did was not unsafe, they landed with reserves intact, so I agree they acted appropriately. However if as has been posted earlier you start getting multiple aircraft using this fuel mayday because numerous cut it thin, then ATC will have to triage who goes first, and you may end up with different outcomes, I mean what if the 3-5 aircraft ahead all were operating on minimum fuel and then a chorus of fuel maydays rolling as they got additional delays to follow the QF. So it has to be asked if they had appropriate fuel to begin with, did they consider alternates, were they completely committed to Perth and if not is a Fuel Mayday appropriate if alternates are available. All questions the ATSB will ask I'm sure.