I feel like all of these laws are being designed backwards. Content providers, like MPAA films, should have to identify what sort of content they are providing. Then I can give my kids a device configured to allow some or all of that at my discretion. Requiring my kids' devices to advertise their age (or their age "bucket", as if that was a meaningful difference) to protect them is not doing me or my kids any favors.
They're actually designed quite well for the intended purpose: mass surveillance and suppression of speech. Don't ever for one second pretend this is about anything else.
Any parents who are pathetically absent from parenting their kids, well, they can just go right on ignoring their kids and letting the kid themselves put in 9/9/99, and consume all kinds of inappropriate crap.
This particular law is respecting everyone's rights.