The Grimm fairy tales (1819) are full of graphical violence, child abuse, anti-semitism, and incest. They are much more harmful than anything that I've encountered on the Internet. So why are we discussing internet harms instead of book harms? Because people are fucking stupid.

And why are we getting concerned about "sharing private information with random web sites" when that's not the solution being discussed. The solution is a simple handshake:

service: Is the person assigned this device old enough to use this service?

idp proxy: yes|no