Here's my 2 cents' worth. Most beautiful ladies (though not all) love to make themselves prettier and enhance their attractiveness to men by dolling themselves up. Also, they don't really like to feel less attractive to other women when walking out on the streets because of the high self-esteem. So, they don't want themselves looking "plain" when others splash lots of makeup on themselves to look pretty. It's actually a form of unfound insecurity when they view other women as being outwardly competitive, probably when it comes to attracting men.
In fact, I think the world is full of beautiful women, interior and exterior. it's just that the mass media often portrays the women in makeup as being hot and sexy so it dampens the confidence and esteem of many women's bareface look. This is the power of mass media and fashion/beauty trends.
As for men, it's a general tradition for them to appear msculine so with or without makeup, they look the "same" in the eyes of women. Women tend to accept their looks because we look more for internal qualities, even if the person looks just average Joe. In the long run, the skin of men is better than that of the women's because it's never touched by cosmetics.