Yes, and it will also almost certainly be misaligned with human values.

As if this will stop it being made, even if it is put into law. All it will do is make it happen without legal and public oversight.

Was it a feather from a green bird, or a green feather from a bird? Are there parakeets where you live?

I disagree with that. Privacy is not the only reason to be against agewalls, though in its current form, it is a big one. Agewalls are inherently discriminatory, and there is no reason children should not see sexual, mental health support, or LGBT+ content online besides puritanism.

The best option is no agewalls

The reason is that humans are expensive, and they don’t want to spend their time programming simply if they can get an AI to give them a functioning project with much less time and effort - at least, commercially.