There's a pretty huge problem here with Aboriginal alcoholism. Lots of domestic and generic violence. So the police slap on the restrictions probably just so they can say they're doing something about it. They banned all full-strength alcohol in Fitzroy Crossing for the same reason, and most of the aboriginal population there moved to Broome or Derby.
It's a pretty big problem, but this is a sucky solution for the non-violent majority to live with. It's not gonna kill us, obviously, but it's a pain in the ass.