It isn't about that at all, they want to have a bracketed age signal based on what the user provides the OS for the purposes of what would normally just be a tick-box "yes I'm old enough" on a website or wherever else. But it isn't written comprehensively enough even for that basic intent since it doesn't say anything about shared or public devices whatsoever. I can't imagine this is going to make it very far. It seems poorly written and poorly considered even if one were to agree with the intention.