I don't care if you have 12 bars on your shoulders, if you arrive without the fuel to get in or to go somewhere else, your options are pretty limited.
I think its just too easy to blame the pilots or say the answer is to carry more fuel. At least the Virgin aircraft had sufficient fuel to divert to YMML. YMEN or YMAV, not to mention YPWR, or possibly even maybe YPED (although it probably had Adelaide's fog).
The pilots made the decision to go to Mildura based on a very favourable forecast that was issued by the BOM despite the BOM knowing or having the ability to know that fog was forming at the time they issuing a good forecast.
Clearly they made a decision to go somewhere that the forecast suggest was blue sky with broken cloud, had fuel and their own company handling services plus a nice passenger terminal that was close to Adelaide so they could finish the trip after the fog lifted with minimal delay. It was a good decision on the information they were supplied.
If the pilots had access to AWIS, a ground observer, an accurate forecast or information on the missed approach was passed to them, then they may have made a different decision.
The funny thing, is that this is a circumstance where a GA pilot might have done better. Because GA pilots don't have the same information resources a GA pilot would probably have pulled out the mobile phone and rung someone on the ground and gotten a higher quality answer than these pilots collectively got from our government air traffic and meteorological services.