Tznius is not just a crowning midah.
Chazal say when Hashem made Chava, he made every limb of hers swear that it would be tzenuah.
When bilaam wanted to destroy klal yisroel, he knew the only way to overcome Hashems love of the yidden was through something he hated so much that the hatred was greater than this love, and that’s zimah. “The God of these people hates zimah,” he said. (This explanation comes from the chasam sofer)
The very essence of klal yisroel is tznius – this is what made bilaam turn his curse into a bracha, when he saw that the yidden had tents that were made to preserve the privacy of each family.
It isn’t just a nice thing. And I don’t care what the Lubavitcher rebbe said about it – if he erred in it, then i can tell you exactly why he did according to reports that are known in the Yeshiva world, but i will not write about it on here because it’s extremely offensive.