This link below from 2018, apparently some residents prefer to sleep at night:
http://www.noaircraftnoise.org.au/index.asp?pagename=Sydney+Airport+Curfew
Its interesting to note that the review of the restriction and curfew was supposed to happen this year and so far, it hasn't.
The (glorified residents action group) noted that while the new planes are quieter, they are still quite noisy. Having been subjected to a 777 flying over my head most mornings, with its wheels and things dangling down I think that is a fair statement. That is to say a two aisle plane that is landing still makes a lot of noise.
I don't mind the noise and I'm quite used to it. Having grown up under the flight path of Boeing 727s, Fokker Friendships, DC-9s and a bunch of other JT-8 equipped thingies I can say you can keep the kerosene soot. That stuff is nasty.
But really, since the last review what has changed?