I understand, but I question the effectiveness of the prior peaceful protests in fighting the legislation in the first place. They obviously didn't go over too well.

It's possible that Anonymous' muckery could stir up discussion about this topic that otherwise would not have existed as the average Australian lapsed back into complacency. It's also possible their attacks will end up being counter-productive. Either way, I have to admire their reckless vigilantism against censorship, and can only imagine the LuLz being generated in the formal setting of Australia's bureaucracy.