Society should not make it illegal. People will look at you weird. If your own belief is that they are all wrong, you're probably happy anyway. What does it matter? At least you have the freedom. Whereas a ban just creates something to complain about, no one can complain about freedom.
Well actually, if I may revise my point, I guess I should advocate that both sides need to give a little, yes.
As to why "they" can't. This could open a whole different sub-discussion in this thread that I don't have enough hands-on details about or the energy and interest to really be having, but I will mention the stereotypical presentation of this point: The west went into the middle eastern countries, raped their resources, ravaged their towns and killed a bunch of people. This happened several hundred years ago and it is still happening. I don't feel a moral inclination to make up for the misdeeds of my ancestors, but I recognize that their actions have created a world situation where we now have a problem, and that encourages me to think solution-wise as I keep going forward. And I don't think a ban on burqas is a solution to a problem, I think it's a band-aid to a sub-problem created by a bigger problem, and in the long run all it will have achieved is more opposition from the Middle East towards the West. If the worry is suicide bombings, then maybe France will be the new target for external terrorist attacks the way America were a few years ago. That's another thing to consider with this ban. A far out thought, but I question the motives behind the ban and whether they are succeeded with the actions taken, and I believe they aren't. Partially, the things I say reflect my opinion on whether it is right or wrong, but partially, the things I say reflect self-preservation. Some times it's good to stand up for what's right, but some times, the most successful long-term result may be achieved by simply keeping your mouth shut.
This is an opinionated matter. It's a sound logic, I just disagree, because I'm very liberal and there is not much other individuals could do unless done directly to me that would hurt/bother me. My outlook on life and people dictates my opinion on whether we should accept it or not.
Here is where I agree with you and acknowledge a problem. They are fast to yell oppression, and I agree that that is a problem/wrong. This ban will in the best case scenario not affect that problem at all. In the worst case scenario, it will be another point on their list of why they feel oppressed.