The influence of agriculture is still strong, understandably.

I'm the 4am-12pm sorta sleeper variety, but it does, you know, make sense to conduct society's business during daylight hours.

It's also an age thing. As you get older, your sleep moves in the early direction and you also need less of it (if you're in good health). My dad's 61 and sleeps 9-to-3:30. I seem to be headed in that direction. I'm usually up by 6-7 even if I go to bed at 2:30, so the smart thing for me to do is sleep earlier.

It's biology. Giving it a moral weight is nonsense.