Here's an essay by Peter Chen at Online Opinion that gives a good summary of the issues, concerns and problems with internet filtering and safety. I recommend it.
But one thing Chen does not address that I think is crucial here is the legal principle of not punishing people for criminal acts before they are committed. By inhibiting people's rights to see what they want online, so long as it is not illegal, clean feeding is an unfortunate step towards government oversight on what we do in any respect. It sets a precedent, and such precedents are hard to eliminate once they enter the domain of legal decision making (called stari decisis under common law).
Yes, I object to the fact that clean feeds are impracticable, will degrade internet performance, and not do what they set out to do (which is protect children), but fundamentally the main reason for not adopting them is that it gives power to governments and their instruments to decide sub rosa what we can and cannot see. Suppose that the present government and all the members of the department of telecommunications are exemplary individuals who not only have our best interests at heart, but do so intelligently and effectively. Can we guarantee that the next government, or a much later bureaucracy, will consist of these people? Not at all, which is why checks and balances are a crucial aspect of democratic government.
And I do not trust this government. They have made way too many religiously-based noises about what is and is not permissible in public. This is to my mind only the thin edge of the constant presumption of religious organisations and culture that they may rightly interfere with other citizens' behaviours, whether they are of that religion or not. That the balance of power is held by a religious political candidate in the Senate is only the tip of that iceberg.
We are a secular nation! It's in our constitution. We do not arrange our public polity on the basis of what suits pastors and cardinals and imams. We do so on legal principles of liberal democracy. For this reason, people are calling for our representatives to oppose the movement coming out of Islam to protect religions against "defamation" speech. Religions have no rights to not be offended by the behaviours of those who are not in their community (and no rights to impose upon their members by legal or other force the views of the hierarchy). And the very idea of handing to potentially religiously motivated censors the power to control what we read, see and hear is just frightening.
I'm not impressed either by the constant refrain by the minister and his allies that to oppose the clean feed is to support child pornography and abuse. Of course I do not. This is exactly the argument that George Bush's administration used to take away civil rights of thousands - if you oppose us you support terrorism. One can be vehemently opposed to child abuse, and terrorism, without wanting to grant unsupervised people unfettered rights to control us. Child porn is illegal - so use the frigging laws to prosecute child pornographers. Give the police the resources they need. There are sufficient criminal investigative powers and laws under which such activities may be prosecuted - you don't need to treat us all as criminals to do so.I think the reason why Labor are so hot for the clean feed is that they really don't want to give the police the resources and to manage them. It's so much easier to simply make other people, the ISPs in this case, stop the porn. Make it their problem and it's no longer yours.
So by all means point out the practical difficulties, but even if you have the perfect means, I am not sure the ends are justified, and I certainly want judicial, community and user oversight on what gets censored and why. And I want a redress system for those incorrectly included (which must include damages - if the authorities don't have to pay for their mistakes, then they'll be a lot less careful). And I also want prosecutorial avenues for those who do abuse this system. Put all that in place, and you may convince me of the rightness of this approach. But leaving it in the hands of Labor or Conservative party hacks who have obligations to religious figures who may have helped them get into power? No way. That takes us back to the Bad Old Days of Mannix. Learn from some history...