Politicians in general are highly ignorant on technology and have no clue about the impact of ideas like this. They get advice from advisory boards populated by political science students that had internships at IT companies and are now 'advisor on AI in government'. Sometimes they get external advice from expensive consultants that tell them what they want to hear, especially if they think they might be able to sell more projects afterwards.

So, a politician who objectively wants to protect children in a modern world will come up with dumb ideas like this and get confirmation that it's not a dumb idea. It's Hanlon's Razor at work.