>>2157516biofag here,
Pale skin is unattractive on a man because it's not sexually dimorphic and it has ties to padeophillic(neotenic) features. There's a reason women universally prefer a man that's "tall, dark and handsome". The reason being, is that those phenotypic traits that women prefer are signs of high masculinity, which signal good genes.
This is why nowadays, with women having an almost complete sexual selection in their favor, will tend to choose males of darker pigmentation. Realize that when an aesthetically man is not possible for a woman to achieve at any given time, she will then pick one who follows what's dimorphically attractive to her given how runaway selection works.
Study 1:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0031703) :
"First, it has been demonstrated that skin colour is a sexually dimorphic characteristic. Men tend to have darker skin than women [28], [29]. Further, in the majority of cultures that have been tested, there is a bias that lighter skin pigmentation is considered more attractive in women [28]. This sexual dimorphism can explain why Black men and White women are considered more attractive than White men and Black women respectively. The former represent highly positive sexually dimorphic patterns."
