It is called the good girl effect. Women are raised with the notion that females should always go out of their way to support and understand others, especially those who really need or deserve help. The more deprived or disadvantaged the persons, the more brownie points are gained in supporting them. This translates into higher social status amongst women.
However in private matters women are still subject to believing in and desiring the idealized, sexist package of the masculine man as the optimal partner, while effeminate males are considered substandard and undesirable.
Normally this discrepancy does not reveal itself as most men try to follow the guidelines of masculinity to make themselves attractive to women. CDs are the exception and by breaking the rules we reveal the motivation behind the good girl effect.