This subject interests me as I have worked as a nude photographers model - not porn, and made a comfortable living for a few years in regular employment.
Now as a nudist who visits nude beaches in male company - rarely is any notice taken of nude bodies by other nudists unless there are extremes. Breasts, penis etc.
Sex on nudist beaches here is not tolerated.
In public ‘clothing optional’ venues,(mixed bathing) I have noticed that more interest is taken and comparisons made of the men’s penis than women’s breasts. The interest in the women’s vaginal area is more related to her pubic hair treatment or prominent Labia if they can be seen - more often than not on women who are completely denuded of hair (very prevalent) or reduced to expose that region. Young teenage bare top girls do attract most attention.
A nude very pregnant woman is more often than not seen as a woman of beauty and most other extreme aspects are ignored as breasts and areola can be larger than normal.
The next most commented form is the figure of a woman. Overweight, firm, shapely etc. obviously her breasts will cause comment if they are on the huge side or firm with uplift and perky nipples. Often enhanced to the extreme.
Attractiveness is in the eye of the beholder. Some have preferences for the extreme features others for the firm and shapely form.
As for men it is basically their penis. Rarely is a comment heard of their body unless he is firm and usually extremely well built. Fit. The overweight, flabby and man boobs do cause some comment at times.
I have nude modelled many years ago and although my figure has now become fuller with age and some droop has developed etc I still attract some attention when naked in company and I have no shame in exposing myself, but not sexually. My pubic hair is manicured to a strip which exposes my labia but rarely do I hear it commented upon unless by other women when discussing the shaping of our pubic hair.
More often than not it is my male friends penis’s that is mentioned when I am asked to comment. Neither are anything but normal, circumcised and nothing extreme although are reasonably well endowed. Their pubic hair is trimmed and testicles hairless and can be prominent in warm conditions. Their performance is most satisfactory and again that aspect can be a topic of comment by some women as I am intimate with both as FWB.
I would agree with the opening comment - I cannot see why nude women can be more acceptable than nude males and I can only attribute that to the size of their penis being the “attraction” and the imagination or otherwise of their erection. Possibly younger children devoid of sex education and discussion can also be a concern.