They're Christian, so you can trust them to have your best interests at heart. The Modesty Survey is a bizarre instrument created by asking young Christian women to put together heartfelt questions about their clothing ("Are bikinis immodest?" "Are jeans immodest?"), and then teenaged Christian boys are surveyed to get their opinions. Because, of course, the girls need boys' advice.
Reading through the questions is weird: they're phrased in different ways, but one of the most common motifs is the "stumbling block". The boys are asked to judge whether an item of clothing is something that might cause them to think wicked thoughts…so once again, the women are to blame for inciting men's behavior by wearing tight jeans or a strapless dress.
They're also explicit about it:
We're not telling you what to wear — we're just telling you what we, as guys, have to guard against. It is God's Word, your own heart and conscience, and your parents and godly friends who should help you decide what to do about it.
What they have to guard against? They should be plainer. "We're not telling you what to wear — we're just listing the stuff that will justify raping you."
I get a Taliban tingle just reading it. It's a far more generous document than anything Islam dictates — young Christian men do not want young Christian women to wear burkas — but in principle, it's the same thing. It's men declaring ownership of women's bodies and telling them what to wear, with the the threat of justifiable sexual assault if they do not obey.
It is a little disturbing, though, to see that their logo has a picture of a woman with a veil over her face.