A device-side IP filter locked behind a password that parents can configure in the device's settings would be much more effective and easier to implement than censoring the Internet. This should be the default solution, yet it's never brought up for whatever reason. Not to mention these online content censorship laws for kids are wrong in principle because parents are supposed to be in control of how they raise each…
The goal is controling the flow of information online. "protecting the children" may or may not be a sincere concern but ultimately censorship is what is desired here.
Read about the infamous EU's chat control and lobbying behind it: https://mullvad.net/en/blog/mullvad-vpn-present-and-then