How are they going to verify it's not some kid telling he's 18 with a fake picture? Demand a photo of driver's license? Got one here, right out borrowed from dad's pocket. The article also mentions inferring age from the usage which sounds as vague as it is.
The counter point is that doesn't this basically mean everyone, including adults, now has to identify in order to use social media? Without a national electronic ID where personal data never leaves government's systems (they've already got it) and the social network just receives a yes/no bit when they ask "is this person old enough?" this would mean a huge amounts of identification data would be willingly and voluntarily "leaked" to foreign private services. Scan your passport and send it to China in order to use TikTok?
This mass identification process could either make also large groups of adult people leave social media sites or condition people to upload their ID data to whatever site happens to ask for it.
I am not protecting non-FOSS practices but you can not register on crypto cx by just showing some papers with not showing your fare. That answers the fake picture case.