It’s really not though.
It’s not like the internet was censored when I was coming up, and I don’t think less of kids today than I do of myself.
Kids stumbling across something when browsing innocently isn’t really a major issue, and if they seek it out: they will find it, you won’t stop them, kids are smarter than you think (just, immature and unwise).
The best method, honestly, is for parents to be forethcoming..
however you have now successfully reframed the discussion into “what about the kids”, when in reality it’s about getting everyone’s ID so that they can better enforce their draconian internet comment laws… the government even outright said this. https://archive.is/3pave
if the government really cared about protecting children, they would’ve made a freely available child protection software that anyone can install in their home network, or subsidised its deployment at ISPs as an advertised opt-in.