If you are making an LLM for children, I have no problem with that! I’m not sure kids being completely removed from the adult world until suddenly being dumped into it is a great way to build an integrated society, but sure, you do you. Build your LLM with safeguards for educational use, best of luck to you!
I do not think it should be the default. I do not think that “adults” wanting “adult things” like some ideas on how to secure a computer system against social engineering should have to seek out some detuned “jailbroken” lower-quality model.
And I don’t think that assuming everyone is a child aligns with “human desires”, or should be couched in that language.