The only concrete claim in that article that I see is insufficient age verification. How does youtube age verify users who are under 13 and trying to create a

The only concrete claim in that article that I see is insufficient age verification. How does youtube age verify users who are under 13 and trying to create an account? Does google search/ad tracking have a mechanism to avoid tracking < 13yos? I suspect they just say "its against terms" but allow it to happen, because to verify children they'd need to collect information on them...