The alternative is to accept that 90% of humans are suffering some form or another of psychosis, because there's very little that even a majority (51%) of people agree on, and that means about half the population is wrong about any given topic. Multiply by the number of topics out there...
So just, you know, don't do that. Select a boundary that places 90% of humanity on the side of "wrong about a number of things but within the bounds of normalcy for the species at large", sprinkle in some caveats about "in the industrialized world" and "for someone with at least a highschool education" and such, and you've got what I was actually describing.
You can't cherry-pick a definition where "AI psychosis" is meaningfully different from "wrong about a few things" without hitting a huge swath of "within the bounds of normalcy for the species at large" - there's just too many people in the category