Hacker News Reader

It's not for sure and you should consult a lawyer, but it's often the case that a court can't order you to do something you can't do.

Yet the law can. All the child protection laws we made years ago have made making unmoderated software very risky.

Notice how they had to make that the law before it became the law. Before it was the law, you didn't have to unless a court ordered you to.

Cannot they just make you implement the ability and make sure you are shut down till you did?

Sometimes, but that sort of thing has to clear a much higher legal bar than making you use a blocking ability you already have. See Apple vs FBI.