content: The deleterious effects of light on humans is documented and obvious. We have little problems with daylight as we evolved in it, but the effects of man-made lighting have only existed for a little over a century. In that time is has radically changed our entire species behavior, the patterns we've established over the course of thousands of years. You can imagine the impact of the effect that various past technologies have had on human beings and the time it took to adapt to them. In short, these things take time to get used to, and time is something of a luxury in the days where humanity is making and developing new technological discoveries at a break neck pace.