The scale on the map may not be obvious but to give an idea of distances, the holding pattern over Goulburn is above a town about 2.5 to 3 hours drive down a high speed (100km/hr) freeway from Sydney.
Folks unaware of holding pattern details seem to think they should only be directly over airports the planes are landing at.
Goulburn is a sleepy rural town with its principle landmarks a giant concrete sheep and a gaol.
Planes waiting to land in Sydney do "mysterious loops" above concrete sheep. http://en.wikipedia.org/wiki/Big_Merino
Canberra, the national capital with all the govt buildings also seems to be a common location for holding patterns for the southerly run in to Sydney and chemtrail believers there are often perplexed why politicians seems to be "spraying themselves"
There is nothing unusual here. The curfew finishes at 2000 UTC and there is a rush of airlines all arriving at the same time. The ULR flights from the West Coast of the US and the Middle East have a dispensation to avoid extended holding so they sometimes jump the queue as well with radar vectoring around everyone else.
We generally hold from FL210 and above so the holding patterns are set to roughly coincide with a standard descent profile.
Throw in some inclement weather and you have a standard Sydney winters morning. I just arrived on the Bangkok flight. We had a ground speed of 647 knots for about 90 minutes as we took advantage of the winter jet stream over Australia. That is my new record for an A330. There wouldn't have been many humans on the planet traveling faster than that this morning.
Another thing to remember with the flightradar24 and Plane Finder plots is that not all aircraft have ADSB, such as the QF 767s. So they don't show up. Another source of Chemtrailer " mystery sprayers".