What are you objecting to specifically? I would think that, if your brain responds to light of a particular color or intensity, it's not going to care that the light source is an LCD.
I am going to need more than "I would think that" if I'm going to believe this, and considering how backlight leakage allows extra white light to emit from your screen, I'd consider that an important enough extra variable that needs to be accounted for before we just start equating "pure" blue lights to the complex lightwaves that come out of an LCD monitor.
Besides, the framing of your question is wrong. I don't even need to come up with a specific reason, the burden of proof lies on the makers of F.lux to demonstrate that their specific product does what it says, and simply citing inequivalent studies isn't enough.
>I don't even need to come up with a specific reason, the burden of proof lies on the makers of F.lux to demonstrate that their specific product does what it says
Man who the fuck cares. Millions of people use f.lux every day - personally, it's the first thing I install on any PC or Laptop I know I'll be using for a while.
It doesn't matter whether you have proof one way or the other.
I give a shit, because if I'm going to use it, I want to know if it's going to do anything. Why suffer through the filtering it does to my monitor if it doesn't matter?
Light is light except when you have multiple sources of light, some white and some blue, due to backlight leakage that happens to varying degrees in every LCD screen.
Do you know how much white light would negate the blue light in your brain, negating the effects? I don't.
Where are the studies testing F.lux directly? This is ripe for all of the best biases to take over, which makes me immensely skeptical.