Melatonin, the hormone responsible for sleep, is manufactured in the eyes, when sunlight hits the retina. You can consider this the first part of the sleep/regeneration process. The second is when the pineal gland, upon the cue of darkness, releases melatonin and triggers sleep.
It's an eloquently functioning system that operates within all of us, but unfortunately, we have become optimized to staring modern living in the eye, at the expense of our sleep.
Blue light exists naturally in sunlight, but the blue light from sunlight is always balanced by other colors in the spectrum, specifically red light(IR) and at certain times of the day purple light(UV), which happen to be responsible for all of the healing and regeneration that takes place in the body.
Blue light from our technology does not have these other colors, causing an unnatural peak in the blue spectrum. This peak is what we really have to protect, especially once the sun goes down.
It's easy to forget how new the phenomenon of light is, especially LED's, whose blue spectrum causes the most disruption to circadian biology. The first LED light was invented in 1962. Mankind has been living on earth for over 100,000 generations!
It's helpful to know the science that exists and how blue light affects sleep. but really, if we take a step back and observe the radical changes that have taken place in such a short period of time, it may be easier to approach the science with an open mind, and the clearest possible understanding of how important it is to block blue light.