Two-factor is one thing. They're mandating client-side scanning in every operating system. This was previously rejected for obvious privacy reasons.

There are already phones with an anti-nudity feature as a parental control option, but the key there is that it's optional. The major pivot with age verification is that all devices treat all users as a child until they identify themselves with a third party. This allows a rhetorical paradox that the controls are only for children, when they apply to adults too by default.