To the OP: An interesting and very relevant question. I can only speak from a guy’s perspective but hopefully I can contribute something. I have seen both the liberal and traditionalist sides of the equation and I have come to the conclusion that neither side has it right. Obviously if a fifteen (or for that matter a twenty-five) year old girl comes to mass wearing black leggings or a miniskirt then she is not only dressing in a provocative fashion but is also demonstrating a lack of respect for the real presence. I doubt anyone on this forum would disagree.
On the other hand I believe that many traditional Catholics, or at least the ones that I have come into contact with, have a view of modesty that is just a reaction to our oversexed culture. The overwhelming majority of the women at the Latin mass that I attended growing up were in what my dad dubbed “the blue jumper crowd.” The name accurately described their tastes in clothes. It seemed that these women, and by extension their daughters, wanted to make themselves look as plain and unattractive as possible, as if dressing modestly and dressing tastefully were mutually exclusive. I think ‘tasteful’ is the important word. Women shouldn’t dress like sluts, but I think they should take pride in themselves. How can they have any self-respect if they do not take pride in the way that they dress and the way they carry themselves? My two cents.