Edit: spelling & TLDR; Sorry for the lil'rant, don't intend this as an attack or to be so long, thoughts just flowed :/ don't read if ya don't wanna

Mandated parental controlls options would be pretty amazing, and relatively easy to implement. Honestly i'd love it. But requiring parents to use them? How do you prove that without another privacy nightmare? Parental control's effectiveness depends a lot usage, a few slips an it's for naught. Plus how would the regulators know what devices the children use? Or if they use/have them at all? Or if parents pay attention to parental controls - if its not just a cardboard vault?

I think the problem is legislators know this and 'terroists' are probably the easiest kinda legitimate attack they have on online privacy. That or they're so tech ignorant they're automatically applying how they'd usually restrict stuff like alcohol/drugs, so regulate the seller/vendor/whatever — not thinking of any more nuanced approacea.

Ultimately its probably best left as a 'educate people, hope for the best' thing. Added to some help from - like you said - mandating parental control implimentation, tightened child neglect/abuse regulation or damn education/schools needs a ton of work too. Maybe make website blocking easier for less tech literate on home networks too. Parent's responsibility but make forfilling that responsibility as easy as possible.

I imagine it might be possible for a parent in the UK to be sued for that already. If that parent breached their duty of care by psycological harm to they child? Maybe you could claim for negligence? I doubt anyone's tried, tbh it's a bit of a stretch and I don't know the law that well ...plus it'd be a right expensive, long process not to mention only a civil case so no criminal consiquences. Unless it's some rich guy's Fuck you case or it's an extreme case borderlining child abuse, not likely.

Sorry again for the wall of text😅thanks