I might be misunderstanding, but I wouldn't call "un-depressed" people ignorant.
I also think depressed people would regress to the average if they weren't depressed. It's not a sustainable way to think harder and open your eyes to the world around you.
Yes I remember reading that too and it resonated. As a slightly depressed person I can't believe the delusionally positive spin people seem to put on everything and nonetheless this seems to be a winning strategy for them. I never could explain that.
Starting with an accurate world model, no matter how dispiriting, seems to be a prerequisite for knowing the most effective action to take.
I also think depressed people would regress to the average if they weren't depressed. It's not a sustainable way to think harder and open your eyes to the world around you.