Here's my slight defense of something like this, in theory. I have not read the text of the bill.

If OSes build a standards-based way to query age of user that is logged-in, where non-admins are not allowed to adjust the age bucket, then parents can configure devices on first use to have an OS-wide enforcement of age controls.

Apps and sites would query the OS, not individual app/site accounts, for user age and act accordingly.

Apps can then lock out certain features like algo feeds and adult content more consistently.

Responsibility for proper use is still on the parent, and no verification process is put upon the operators of sites.

Not sure how I actually think about this; I'm only putting this out for discussion.

Storing age is no different to storing name or address to me, it’s just a field in /etc/passwd, and root can change it.