I think part of what confuses me is what actual flight has daylight and is timed such that it is a moral imperative (like some on this thread seem to imply) that everyone needs perfect sleep? Most flights that go through daytime are at best "nap" flights: LHR-SFO, daytime SFO-ICN, etc. You are leaving in your morning and arriving in the evening so it would be weird to sleep for nine hours in between. If you're just snoozing a bit in the middle of a long day, that's what the eye mask is for. I might not want to nap at the same time; maybe I want to spot some icebergs. I will close my shades when taking a nap, and open them if I'm awake and want natural light.
About the only exception I can see here is something like SFO-LHR in midsummer where the sun never quite sets, but still... that's what the eye mask is for. I buy my window seats because I want to look out the window. I don't think that's outrageously selfish.