Map of countries with bans: https://upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Burka_ban_world_map.svg/1024px-Burka_ban_world_map.svg.png
Map of countries with bans: https://upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Burka_ban_world_map.svg/1024px-Burka_ban_world_map.svg.png
I mean I'd be willing to discuss the topic if there was a justification that didn't involve thinly veiled racism, but I've never heard one. In fairness I haven't really looked into the topic directly because of this assumption.
One argument that comes to mind (I haven't given it much thought) is that most cultures (non-burqa wearing cultures) have a strong cultural impetus to see a person's face, show their face. This could be said to be equally as important as the cultural impetus to wear a burqa.
There's women's liberation issues too.
It's hard enough to use Islam to justify the need for the burqa, which is why most Muslims don't.
The justification, I think, is that it's "clothing that promotes religious extremism" ("宣扬宗教极端思想的服饰")
Sorry to be a bit terse, but enforcing cultural behaviors sounds like idealism and a wide road to racism to me.
To address the sexist culture around the burqa with a ban is just treating the symptom, something that I would expect from liberals, but I would hope that most of us on the Left would have a deeper analysis. Changing the economic and legal relationships that enforce patriarchy will do more to liberate women, and the burqua will fade away (most likely, but at least it'll be a free choice) over time as women will more easily be able to leave a conservative/patriarchal culture if they so choose. This avoids replacing sexism with racism.
It's hardly "liberal"