The reason the new, pure Islam of the Muslim Brothehood requires absolute separation of men and women, and hiding women in the anonymous hijab? The men are scared of the women!
From Infidel:
As women, we were immensely powerful, Sister Aziza explained. The way Allah had created us, our hair, our nails, our heels, our neck, and ankles - every little curve in our body was arousing. If a woman aroused a man who was not her husband, she was sinning doubly in God's eyes, by leading the man into temptation and evil thoughts to match her own. Only the robe worn by the wives of the Prophet could prevent us from arousing men and leading society into fitna, uncontrollable confusion and social chaos.The woman's form created to be arousing to a man? Check.
Deliberately leading men into temptation is sin? With you so far.
Wearing the hijab and social chaos are mutually exclusive? Whoa! Stop right there!
Women are so powerful that they must be covered up, and men are so weak that they can't be trusted to be responsible for their thoughts and actions. Going to this extreme is an easy way for men to avoid the nuisance of personal morality and responsibility. That said, I'm not sure the pendulum hasn't swung too far the other way in the Western world.