Also see the UK as well for an example of how previously unregulated speech has become regulated because the authorities have pushed over and over again, backing off every time there's a loud enough protest, but trying again after a short time.
So exactly what parent said, happened.
They do because it's true and that's exactly what the law says.
Digital Economy Act 2017 14 (1):
>A person contravenes this subsection if the person makes pornographic material available on the internet to persons in the United Kingdom on a commercial basis other than in a way that secures that, at any given time, the material is not normally accessible by persons under the age of 18.
Section 23: Regulator’s power to require internet service providers to block access to material
(1) Where the age-verification regulator considers that a person (“the non-complying person”) is—
(a)contravening section 14(1), or
Go read the "commencement" section - it's actually eye-opening to do this for other laws you've heard are supposed to have drastic effects.