The law does not dictate collection of biometric data, or restricting access to the entire site, and preventing authors from editing their own posts. The law only dictates that reasonable measures must be taken to restrict adult and harmful content to persons over 16 years old. There are many ways to verify age, including algorithmic, but substack chose to bar access unless consent is given to biometric information being shared with their vendor. Most accounts here are connected to stripe, with bank account details and tax account details being already registered, so the present policy is just opportunistic, coercive harvesting of private, sensitive, proprietary information. Biometric data is valuable to them, and they just don’t want to pay for it.