Yes, some people might reasonably not want their children to run across pornographic material on the internet. Here are some other things some people might reasonably not want their children to run across on the internet: Anti-religious material. Religious material. Depictions of violence. Any mention of prejudice against racial minorities, women, etc. Websites offering do-my-homework-for-me services. News about upsetting things like tens of thousands of children starving to death every day in poor parts of Africa.

I hope it's clear that the internet would not be improved by having opt-out filters for all those things. I think it's clear, in fact, that the internet would not be improved by having opt-out filters for any of those things.

Yes, I hope my daughter will learn about sex in better ways than by stumbling across porn on the internet. And I hope she'll learn about those other things in better ways than by stumbling across them on the internet, too. It is not the government's, or my ISP's, job to make that happen by making things harder to find online; it probably won't work, and it will probably break other things (as such filters always have in the past), and it's the wrong way to solve the "problem" anyway.

And I also hope that if in the fullness of time our daughter wants to find porn on the internet, she will be able to, and she won't be (or feel) obliged to disclose the fact to her parents, and doing so without telling us won't require her to seek out dubious illegal channels which are likely to be full of stuff much "worse" than she'd easily have found without all the censorship.