It's interesting that although male nudity is considered more "threatening" or "obscene" in mainstream society, men are more likely to be naturists than women. Nude women have been the object of art for thousands of years, yet they seem to be greatly outnumbered in the FKK movement.
It seems like naturism for either gender generally still carries a social stigma. What is more the problem is that women have been conditioned to believe that their nude body is supposed to be sexually pleasing for men and perfectly proportioned (according to Western standards of beauty), and is also inherently shameful. This certainly manifests itself in women's reluctance to be nude around men, but I think that women uphold these ridiculous standards amongst other women as well.
As a naturist individual, I believe that true naturism seeks to break down the boundaries that society has erected between man and woman, majority and minority, young and old, etc. Over time, I am confident that the naturist movement will attract more and more diverse groups of people to it, including women who realize that naturism is intended to be a safe space in which society's standards for nude bodies hold no value.