Per the aggada she immodestly exposed (her hair) while sitting outside their tent, deliberately shocking the party of Korach, and thus saved her husband. Sensitivity to tznius isn't a sure sign of a tzaddik. Context is relevant: ideas of tznius vary among eras. But the ban on discussion of the school and its staff sounds like a cult. Certainly there's motsi shem ra, for politics or gain. In the aggadta, the son of Shimon b. Shetach; in our era, IMHO R' Matis Weinberg. But there are plenty of cases where black-hat rabbe'im were caught stealing or abusing students. One in NY pocketed $400K in gov't money; another rav was sentenced to 7 yrs for abusive conduct. Demanding "what is said about the high school and those who work there must be positive" sounds like Waco or Jonestown. How do such schools get such positive rep? Puffery, it seems. Rabbis once boasted Orthodox had fewer hangups as they studied details of conjugality very early. Now reverse seems true. Go mod orthodox.
Three Palestinian teens killed by Israeli army fire during protests near Gaza border (Haaretz)
from the article: Ultra-Orthodox school bars girl over her 'mother's immodesty'