tl;dr: There is a kind of nocturnal society that most people just aren’t aware of. This is all entirely true, making people with normal circadian rhytm to work night shifts is deleterious for their health. (And the worst kind of schedule is when day and night shifts are alternating, this is an absolute nightmare for your endocrine system regardless of your chronotype). I agree with most of what you said but I definitely wouldn’t go far enough to call it a nocturnal society. I worked night shifts for over a year in a dementia care home.