This topic has been chewed to death, here, there and everywhere.
Who are we to judge how others dress? Do we want God to judge us on our flaws? Just because the way that somebody dresses is not tzanua according to you and yours, does not mean that it is worse than your discussion of them?
Have you ever thought that that woman (or man) with the short/tight skirt or whatever article of clothing–or lack of–that she (or he) is wearing, is working on other midot or mitzvot? Maybe she (or he) is perfecting her (or his) sh’mirat shabbat, kashrut or a mitzvah that is ben adam lechavero?
If all of our sins were visible and magnified like the issues of tzniut are, I’m sure that those who are doing the discussing, judging and condemning will have flaws of their own, exposed for all to see. Just because one’s flaw is more obvious than another’s, does not mean that it is worse. And the fact that one’s weak point may be tzniut, does not give you or me permission to discuss their shortcomings.
Nobody here is a tzaddik or tzadeket. We all have to work on ourselves. I may need to add a few inches to my skirt and top, and somebody else may need to work on their yirat shamayim, mitzvot of ben adam lechavero and the practice of being dan lekaf zechut (all of which I should work on too).
Just one more thing, please. The shells under dresses. For the love of God, give people a break!!! It’s hard enough to keep tzniut as it is, and I can’t even believe that people would say that wearing a shell under a sleeveless dress or spaghetti strap one is not tzanua. You’re choking people. Literally.