I so believe the opposite of this IF you come at the right ones the right way?
Which is to say, once you read (or skimmed) enough of them, it's easy to get a sixth sense of the "intelligence" and "motivation" of the writer, and the sincere ones, even if not smart, are still pretty enjoyable if taken with many salt grains, and I'm a sucker for them (again, not in terms of following exactly what they say to do, but appreciating the motivation and good-intent of the author and possibly picking up something along the way.)
They'll have names like PSYCHO-CYBERNETICS and just be like "try to be nice to people and sit down and be quite a few times a day."
A sort of perfect example would be the fictional "The You You Are" from the TV Show Severance. I hope they actually write it, I know I'd LOVE it.
https://severance.wiki/the_you_you_are_book