I'm not for these draconian age verification nonsense, but this isn't a valid argument.
This is the way it works with e.g. alcohol and cigarettes, most places. Famously kids can just get a beer from a random fridge and chug it, but someone 16/18/21+ will be responsible and everyone seems mostly fine with this.
I regularly talk to other parents at the school gates who have no idea that permissions on mobiles even exist, let alone that they can choose what they let each app have access to.
The general public people just dont care.
(fwiw I regularly talk to parents who are quite aware of various parental controls and use them effectively, combined with talking to their kids and just general good parenting practices)
Is it bypassable by a sufficiently determined child? Yes, but so it is the current age verification nonsense.
No, that's not the case.
just like you already are responsible for what happens on your free public network (torrenting, hacking, CSAM, etc.) in most jurisdictions
(for what its worth, i think age verification is dumb. but it looks like we're getting it one way or the other)