The problem here is that girls are never taught the reason for Tzniyus. There is no chinuch – there is just control. Maybe a Bais Yaakov does not want to teach a girl about the yetzer hora of men in regard to tzniyus. I don’t know. My daughter is 12 and has no clue about any attractions between men and women. She looks like a little girl and for the life of her has no idea why she can’t wear short sleeves. She listens of course – but it is a real mystery to her. I of course will try to guide her as she grows older. But if all she hears from school are rules – and let me tell you in some of the Bais Yaakovs in NY there are insane ‘Tzniyus’ rules – then I am afraid that she might rebel. Some schools tell the girls that a pony on the side is not tzniyus, that their bangs are not tzniyus, that their long skirts are not tzniyus. One tzniyus teacher in a BY in brooklyn looks under the girls sweaters to see if their tzniyus button UNDER THE SWEATER is unbuttoned! Of course this turns off tons of girls.
Girls have to be taught the meaning behind tzniyus – they just can’t have rules shoved down their throats. It might be a touchy subject – but it has to be done. The schools have to Mechanech – not just preach!