I wonder where all the voices for parental rights and responsibility are? If parents don't want their teenagers accessing adult sites on the Internet — which is quite reasonable — then they can avail themselves of inexpensive technology like Net Nanny and similar products on their home networks and their children's phones and other devices.
I have a Samsung phone, and it comes with access to parental control devices preloaded.
That sounds like an actual solution that doesn't involve collecting personally identifying information from millions of people.