Alien Warrior = Dark Skin?

[One Above All]

I assume that "dark" means "darker than Caucasians". The question is, why would aliens be as light or lighter than Caucasians, when skin color can go from white (no or little pigment) to black (lots of pigment)? Which do you think is more likely:
Getting the number 3, when someone else spouts a random number between 1 and 10, or getting any number except 3?
Yes, there are more actors with "dark" skin who play aliens than Caucasians. That's just because, statistically, you'd be more likely to find non-Caucasians than Caucasians. Actually, if you focus on just one skin tone (and not a whole spectrum, as you're doing in the OP), you're more likely to find every skin tone except that one. Assuming all skin tones are equally distributed amongst the species, of course. Given that these are "aliens" we're talking about, I think it's the best bet.

...Or it's just plain old racism. Take your pick.