There is conclusive evidence that blue light does not affect sleep in any way as large as people expect. We're talking about 1 minute on average change in sleep duration.
The f.lux guy is intellectually dishonest. He's been at it long enough. He's got a lot of axes to grind. I don't see any trials in https://justgetflux.com/research.html.
f.lux use by normal people and other similar stuff is a good canary for how sophisticated a person is.
Many, many adults suffer from going to bed too early, not too late, especially older adults, a huge number, millions. People have been trying blue light as an intervention for them, and it doesn't work.
Here's "blue light sleep":
https://clinicaltrials.gov/ct2/results?term=blue+light+sleep...
Do you see any affect of blue light on sleep? Or do you see conclusive evidence that blue light does not affect sleep?