Hefzi - I think you could well be right.
My objection to the whole thing is that in no mosque I have visited (ok, only about 3) has a 7 year old girl been required to cover her hair. And it could well be a confection by over-weaning liberal teachers.
Whataloadof: see, if amongst those Yr 7s there are muslim girls (for example) who want to wear the Islamic swimming costumes I have seen, then good on them - I am v happy for them to do that. The yr 7 girls who wear swimsuits are simply doing what is a cultural norm for them. By Yr 7 sex and sexual attrtaction (as well as a sense of sexual modesty) is an issue. At age 7 it is NOT. And IME 7 year old girls are not required to cover their hair in all mosques.
"Do these girls have freedom within their communities and families to choose not to carry on being a muslim." They do. My SIL is from a muslim family , and she married into an culturally Hindu family, her sisters took up hijab fairly recently not having been brought up with it) , and everyone does their thing. The whole extended family celebrate Eid, and Diwali, and Christmas. Because it's like that recent FB thing - "A Christian, a Muslim and a Jew walk into a café. The Muslim orders a big pot of tea. Then they all sit down together and have a good laugh because that's what people do when they aren't behaving like arseholes'. I do stuff that they don't do, they do stuff that I don't do. They don't expect me not to serve alcohol at family get togethers, we don't take alcohol to the muslim homes when invited. At the beach their dd's wear swimsuits with cycle shorts underneath, I wear a bikini. Their DH's never lift a finger in the kitchen or clear plates, my DH cooks and DS clears plates. And DS clears plates in other people's homes too.
But nowhere do 7 year old girls cover their heads, in this set up.
As was said below on this thread, the hijab, the veil, predates Islam. I is cultural, tribal, it is very much about keeping women out of the sight of other men and keeping the tribal bloodline 'pure'. That is its origin.