(*All of the above also applies also to the SSPX priests, for in 10 years I have not heard or read one sermon addressing this all important point.)
You may have missed this explanation by Fr. Peter Scott: "
a decree of the Sacred Congregation of the Council of January 18, 1930:His Holiness, Pius XI, has never ceased to inculcate in word and writing that precept of St. Paul (I Tim 2:5, 10) —"Women also in decent apparel; adorning themselves with modesty and sobriety …as it becometh women professing godliness with good works."
And on many occasions the same Supreme Pontiff has reproved and sharply condemned the immodesty in dress which today is everywhere in vogue; even among women and girls who are Catholics; a practice which does grave injury to the crowning virtue and glory of women, and moreover unfortunately leads not merely to their temporal disadvantage, but, what is worse, to their eternal ruin and that of other souls.
It is no wonder, then, that bishops and other Ordinaries of places, as becomes ministers of Christ, have in their respective diocese unanimously resisted in every way this licentious and shameless fashion and in doing so have cheerfully and courageously borne the derision and ridicule sometimes directed at them by the ill-disposed….
There is a second reason why modesty of dress is especially applicable to women over men. It is that there is a special form of immodesty that is characteristic of our modern times, and it is the immodesty of women wearing men’s clothes, most notably pants and shorts. This undermines a woman’s psychological perception of herself, and of her difference from a man, which in turn de-feminizes her, erodes natural respect between men and women, removes the defense to over-familiarity, and eventually degrades the relationships between men and women to the level of sensuality. It is this form of immodesty which is ultimately by far the most destructive of human relationships and of the virtue of purity.
If, therefore, there is certainly a standard of modesty for men, it must always be remembered that the battle for women’s modesty is both much more crucial and much more difficult to win.
Real men will, however, teach and lead by their example. If they have a difficult time insisting on the modesty of their wife or daughters, they will remember to practice very precisely all the four kinds of modesty mentioned above, and their admonitions will bear fruit. [Answered by Fr. Peter R. Scott]" http://archives.sspx.org/Catholic_FAQs/catholic_faqs__morality.htm And this article was about someone who complained the Society was too strict on modesty, "Finally, let’s discuss “rigidity.” As opposed to the modern world, I will say unabashedly that the priests of the Society of Saint Pius X take modesty very seriously. It is taught by word and example in the parish and the school. And the priests are not afraid to preach about that subject (though it is not as if this is the topic of continual sermons, either). However, the implication (ended with an exclamation point) that truly minor (though not unimportant) infractions against the virtue of modesty are met with some sort of vitriol, as a matter of course, is absurd." https://angeluspress.org/blogs/blog/virtues-are-inconvenient I believe inculcating modesty and purity is very important, but it must be done in a holistic way.
Teach children to love Jesus in the Eucharist, to spend time in prayer and before the Blessed Sacrament especially, and the constant efforts necessary in the pursuit of holiness will crowd the temptations to immodesty out. St. Alphonsus recommends the 3 Hail Marys Devotion morning and night, and the frequent invocation of the Holy Names of Jesus and Mary, as means to preserve chastity and purity. Daily family 15 decades Rosary, wearing the Scapular and being consecrated to the Immaculate Heart likewise are a must. Why was the Samaritan woman in Jn 4 living impurely? Because she never knew the love of God. When she came to God, she gave up sin.