Actually, I have no idea. The Aussies sure don't seem to like Halloween, though.
In fact, I'm surprised by the bitterness, it really is one of my favorite holidays - good for kids and adults, none of the pseudo-preachiness of a religious holiday, and the parties often involve people dressing up as vampires or "naughty nurses". Maybe there was some pumpkin-related national disaster I don't know about.
Its one of my favourites as it just seems to be about fun. But Aussies are a weird bunch. They'll take on Mother's / Father's day to receive gifts, but when it comes to giving lollies to children escorted by 19yo Candice (naughtily dressed up for a later party) its called American nonsense.
Real Users find the one combination of bizarre input values that shuts down the system for days.