For very good evolutionary reasons. Mans sexual value is primarily derived from his ability to provide and genes (height/strength). Womans sexual value is primarily derived from her looks and child-raising capicity. To believe men and women are judged according to the same criteria is some kind of modern feminist autistic nonsense. A woman being fat is like a man being unemployed and short. Luckily for women, their weight and therefore their sexual prospects are entirely under their control.