I don’t know for sure but I assume of it is because light roofs require more maintenance to look as nice. Nothing shows up on a dark brown or black roof. A white or light grey would show dirt and debris. I don’t want to waste my time washing my roof because my HOA doesn’t like the way it looks.
i guess so? But a dark grey roof is already literally made from asphalt. It can’t look much worse that proto road material.
Even then you could easily do a brighter grey color. Doesn’t have to be white, but nearly every roof i ever see is either black, some variant of a dark color. Not a lighter grey or red, those are lot less common.