What about the people who live in places which receive little to no sunlight?
Our bodies adapt to the place where we spend most of our time. Places like Antarctica, Northern Europe, Russia, Greenland have extremely cold conditions and the sun is only present for a few hours of the day and for a few months in the year. People living in such places have adapted to living with minimum exposure to sunlight.
But for the majority of the world, we receive ample sunlight, and thus we must take the maximum benefit of sunlight.