This is just large media companies like Meta, Tiktok, and Youtube pushing responsibility for verifying their users are old enough onto someone else to dodge liability for the addictive garbage they produce.
Because having to verify your age with multiple different companies is clearly superior to just doing it once and being done with it?
Look, I get it when some people say they don't want any age checks. That's how the internet used to work, and it's not entirely unreasonable to place the burden of parenting (ie keeping kids away from age inappropriate content by enabling the appropriate parental controls) on parents. But a few states already have age gate laws that work the way you're describing (at the site level) and:
It's annoying for adults.
It doesn't work to keep kids away from inappropriate content.
There's no way to implement the age checks without massive privacy concerns.
Given the choice, I'd prefer no age checks at all - but my preference for a lesser evil would be to just verify once with Microsoft/Apple/Google (in all likelihood, they already have the information needed to determine I'm an adult anyway) and be done with it forever.