I am the PP and I agree that if both men and women adhere to a similar notion of ‘modesty’ within a religious framework, it is less problematic, but that is within a religious context. I don’t think this word can or should be secularised.
For me, the concept of modesty has either solely religious connotations or patriarchal. It takes away the very practical reasons people wear clothing, and typically women.
Pre-Victorian (and I'm skipping over the Protestant dress codes with collars here) women wore top-down shifts which made breastfeeding efficient. In some climates and cultures , limited clothing is much more practical due to resources, heat, and living conditions.
Scandinavian countries are much more relaxed about nudity and limited beachwear. This is weather influenced as they need to be completely bundled up in the winter so covered up clothing isn't seen as modest - it's critical in cold climates and applies equally to men and women.
It's the Abrahamic religious cultures that have given us the veils, the obsession with virginity and control of women and influence the sexual obsession with the facts of our bodies.
For us more practical minded, agnostic women, sometimes shorts and a thin top are worn for our sole comfort. I don't want to worry about the modesty needs of people who should mind their own business. It's the male gaze that pushes women and men to obsess over policing women's bodies with discussions over modesty and I'm not interested in catering to this.