It's not because that's not the typical case. LLMs encourage people's delusions by default, it's just a question of how receptive you are to them. Anyone who's used ChatGPT has experienced it even if they didn't realize it. It starts with "that's a really thoughtful question that not many people think to ask", and "you're absolutely right [...]".
> If AI is better at meeting human needs than actual humans are, why let perfect be the enemy of good?
There is no good that comes from having all of your perspective distortions validated as facts. They turn into outright delusions without external grounding.
Talk to ChatGPT and try to put yourself into the shoes of a hurtful person (e.g. what people would call "narcissistic") who's complaining about other people. Keep in mind that they almost always suffer from a distorted perception so they genuinely believe that they're great people.
They can misunderstand some innocent action as a personal slight, react aggressively, and ChatGPT would tell them they were absolutely right to get angry. They could do the most abusive things and as long as they genuinely believe that they're good people (as they almost always do), ChatGPT will reassure them that other people are the problem, not them.
It's hallucinations feeding into hallucinations.