That doesn't work either. The technology itself requires training on absolutely bonkers massive datasets to function the way we expect it to. You can't just "only train it on Mr. Rogers and Sesame Street" because that won't result in an LLM model anymore, it will simply be a tiny "Mr. Rogers and Sesame Street word model" with such extremely limited capabilities that you won't even recognize it as an AI or chatbot at all. No matter how much you train it on such a limited dataset it will never appear any "smarter". Having read and consumed almost all of humanity's entire corpus of collective knowledge and fiction and having near instant access to everything added to it over time is the special sauce. That's what it takes to make it appear "smart". But it's not. And after undoing that then restricting it to such a limited dataset, it will never even appear to be in the first place.
Even if you expanded it to be trained on every possible "suitable for children" piece of content you can find, even if such a thing were possible to define and acquire, there is probably simply not enough such content available in the world to train something into the same sort of thing that we currently use for chatbots in a safe way that you can be sure it will be safe and suitable for children. Insofar as anyone can be sure about a random typewriter not eventually producing Mein Kampf Children's Edition. It's random, it's just an infinite generator for finite probabilities, the most we could perhaps say is that it would probably be safe with a very generous statistical amount of certainty. But not actual certainty, because it's random and safety is not a fixed target anyway, it moves.
The whole thing is a fool's errand. We're being fed bullshit for profit and to misinform and manipulate us. It was bullshit from day 0. It's still bullshit. It was never about and will never be about anything other than profit and manipulation. The technology itself is very interesting and MAY have real applications, with real value, but right now what it's being sold as and for is almost exclusively pure, high-grade bullshit, that the entire economy has started snorting and getting high on thinking we have finally reached the tech singularity, won capitalism and solved all the world's problems. They are wrong. We will have to be ready to make sure the consequences of them being so wrong are not inflicted on innocent people, because if we can do that, then the consequences will simply be really funny and satisfying to watch. I'm not holding my breath for that, but a man can dream.