It's to move to a risk management based society. Look at the sociology behind all of this and you would see a counter example. this was already being accelerated the first step was facial recognition years ago. Surveillance states are defaults in risk management societies. In a nutshell if we treat everyone like a criminal then its only a matter of time before we catch someone is their consciousness going forward.

Australia pressed it, as a result of parents who have genuine concerns about social media addiction in kids (but who aren't willing to do anything about it themselves).

And there's also this which explains why the implementation is the most annoying way possible. If I had my way age-verification would be solely tied to the addictive features of social media, but if that were the case the big tech companies would just lose users and wouldn't be able to insert themselves as an age-verification middle-man.