Hairy - those pictures, that article, it's scary - clearly pointing out that those are women just like us, who are not freely choosing to wear a scarf, but are being forced.
And also a big YES on your point that it's not a cultural norm, but a sexist norm, as men are not required to do any such thing - and the cultural norms for men (eg. circumcision) aren't enforced by law, unlike women's dress code.
And of course it's different to France - yes, I'm a Brit, so forcing anyone to wear (or not wear) anything is against my culture, but a couple of towns in France declaring that women on the beach can't wear one specific type of swimming costume (and being swiftly condemned by the French Government) isn't the same as arresting any woman who doesn't cover her hair.
I have no general problem with headscarves, I wear hats, I live in the med but am pale, so I generally cover my arms and legs, and I would cover up when going into a religious building, but that's by choice.
Making it an offence not to is what makes this sex discrimination, and therefore unsupportable.