I think the loss of privacy for adults is the actual intention; they want all our movements linked to our state ID
like most moral panics “the kids!” is a bad faith smokescreen for the encroachment the fascists desire
A poorly understood problem with age bans for social media is that all the adults give up the privacy (since that's what it means to verify your age) and the kids will still be social on the Internet, because, well, they're kids and it's the Internet.