The point is skin color isn't supposed to matter at all. These same people will say, "it doesn't matter if you're black, white, brown, orange, green, purple, polka dotted, etc"...so they list other unnatural colors for skin to show just how "tolerant" they are. BTW, gingers with a tan tend to look orange, so it's more natural than green or purple.
If they have to fall back on skin color to criticize a man, they don't really have much of an argument in the first place; it is mean-spirited, racist (yes!) and is a sign of desperation.