I think there is an unspoken concern among policy makers about how sophisticated AI is becoming. I think they envision a scenario of swarms persuasive AI bots controlled by an adversary, pushing people to elect bad actors with bad policies. So the main objective isn't to protect the children it is to eliminate anonymity! At some point these age verification requirements will go from answering a simple question to providing your ID. I'll add that there is also an aligned interest with companies that rely on ad revenue as they don't want to serve ads to bots!