I see your point. But couldn't you use the same argument without AI? The internet already has multiple mutually-exclusive narratives, and all of them have people that take them as reality.

I would argue that kids that grow up in that context either pick a side and engage in the eternal narrative war, or become cynics and despair, thinking that there's no objective truth.

Adding more narratives, now generated by AI, doesn't (IMO) change the current playing field that much. My bet would be that kids will become even more cynical: "if a machine can make anything sound like truth, there probably isn't any objective truth"