It's dual use. It is about protecting children, but also along the way these other properties happen to come along. Thing is, with enough cryptography, we could get a way that this would work, but it's too complicated, which results in you being right after all.
> with enough cryptography we could get a way this would work
No amount of cryptography will stop a parent from handing a verified device to a child. Parental controls (however effective you think they might be) have come enabled by default in the UK for the last decade and literally need to be turned off - which is exactly what will continue to happen.
It's dual use. It is about protecting children, but also along the way these other properties happen to come along. Thing is, with enough cryptography, we could get a way that this would work, but it's too complicated, which results in you being right after all.