"they're not defending restrictive dress on religious grounds but rather defending religious women's right to participate in what outsiders view as oppressive"
Exactly! As a Christian woman who usually chooses to dress modestly, enjoys cooking and cleaning, and regularly says things like, "Honey, I didn't get married so I could kill the spider," I believe that feminism needs to be respectful of all women's choices that don't cause harm to others. I find it just as anti-woman if a feminist tells me I'm less of a woman for choosing family over career, as I do when a Pastor tells women in the congregation they need to be guardians of men's virtue by covering up their tempting shoulders.
I was raised near the beach, where much of my free time was spent in daisy dukes and bikini tops (when I could rock that look, lol) and when I moved to the south, my female landlord was scandalized by my wearing a tank top. I imagine if I had been raised in a culture that considered a tank top to be a sexual overture to every man within eyesight of me, I might feel really uncomfortable wearing tank tops, however oppressive that might seem to a person raised on the beach in NJ. And if I had been raised in a culture that considered showing my hair to be similarly sexual in nature, I might not feel comfortable forgoing the hijab no matter how oppressive it seems to someone raised in East Texas where you can bear your hair but not your upper thighs without fear of castigation.
So I agree that certain sects of Islam retain the ugly tribalistic degradation of women as a major aspect of their culture and that is wrong, obviously. But to tell a woman who was raised that way that she must westernize her dress because the way she was raised is wrong, seems to simply be a revictimization of an already victimized woman.