When I was growing up, I didn't see my maternal grandmother with gray hair until the end of her life when she was too ill to leave the house to do anything except go to the hospital. I recall her as having extremely pale skin which got paler as she grew older and very black hair. Compared to my paternal grandmother, who let her natural aging process run its course, my mother's mother always seemed a little unearthly in appearance. Even as a child, I felt she never looked "right".
As we age, it is natural for things to go south as gravity drags us down and for things to get paler. This is because the number of cells which contain pigment is reduced and skin gets thinner. Seeing pale skin with dark hair is just weird-looking to me. Lighter hair, by virtue of graying, goes hand in hand with lighter skin. I'm sure that has been the natural order throughout the history of mammals with fur or hair. When older folks dye their hair black or a dark color, it just feels "wrong" and is one of the clearest indications that someone is rejecting their age rather than settling into it gracefully.
Like my granny, many Japanese women (and some men) dye their hair black or a very dark color as they age. Since the overwhelming majority of Japanese people have black hair and don't dye their hair lighter colors as they age to match their skin tone (an option which is more palatable to foreign people with their greater genetic diversity in skin, hair, and eye color), I constantly saw people (again, especially women) who rather obviously and sadly tried to hang on to their youth.
I don't miss seeing so many women with unnaturally black hair and pale skin and thinking about what it said about how they regarded themselves as they aged.