In principle I agree with keeping some content away from children, but I don't think any of the implementations will work without causing worse problems, so I disagree with implementing those.

> in the day to day practical way

There's a world of difference between practically required and it being illegal to use anything else, even if initially for a small set of population. You still have a choice to avoid those now. Moreover there is a fairly large subculture of gamers etc opposed to these movements, and open computing platforms will take a long time to fizzle out without intervention.

If you mandate locked down devices for kids, it will very quickly become locked down devices for everyone except for "licensed developers", because no one gets a bunch of new computers upon becoming an adult, and a new campaign from big tech will try to associate open computers with criminals.

Though the fact that it's hard to archive too, perhaps make it more ephemeral on the whole, since few people will have a backup when do you get around to remove it.

Why do you think there would be regulation to honor the "underage signal", but not explicitly ban social media sites for "unverified" users?

> seems pointless to avoid using that capability

It's not pointless, because relying on it will soon make these locked down devices mandatory for everyone under 18, and they will keep using it past 18. Everyone will lose general purpose computing, along with adblocking and other mitigations that protect you from various harms. It also leads to widespread surveillance being possible as parents will want to be able to "audit" their teen's usage.

> put an additional system of control front and center

The problem should be controlled at the source, not the destination, if feasible.

As opposed to censoring internet content in general, which does not work because there will always be sites not under your jurisdiction and things like VPNs. I don't support any such censorship measures as a result.

Overall I think while there is a reasonable argument in favor of age verification for some types of sites, the harms of implementing it would drastically outweigh any benefits that it should not be done.

Parent's proposal is better in that it would only take away general purpose computing from children rather than from everyone. A sympathetic parent can also allow it anyway, just like how a parent can legally provide a teen with alcohol in most places. As a society we generally consider that parents have a right to decide which things are appropriate for their children.