The other angle is that Australia has always had censorship. Radio and TV are censored. Video games were logically censored to keep things in line with alread excepted policy. I'm personally surprised that censorship of the Internet has taken so long. I used to run a PC repair business and every customer with children and some without were concerned about what is available on the internet and many asked me to install Net Nanny or some other similar service. Any internet filter that filters out things like child porn and bestiality will be, except for some vocal small groups, quite popular here.
As for the 'oversights' outlined by the parent, Australians trust our governments a lot more than people in the US. Up until not too many years ago all of our public utilities were government owned, we have free government run or supplemented health care, education and payments and job training for the unemployed. It is quite natural to us that there should be censorship and I think the majority if Australians would be quite happy for the government to be doing it without questioning things too much.