You're probably right, but such is Telstra's regular data pricing, by comparison this isn't bad. So yes, we get screwed on data. On the plus side, Telstra is by far the fastest network, and, importantly in such a large country, its coverage is the best by a long, long way.
Vodafone and Optus should be soon to release their pricing. Optus actually has somewhat casually let their pre-paid pricing out, and it's very close to Telstra's (in price, not in performance and coverage).