i think they're right to ban it. yes, i know that the law stems from the far right in holland who are a dangerous bunch and who totally hate muslims, but whatever their motivation, the result is still positive: sending the message that this kind of oppression will not be tolerated in modern western societies.
i've had this debate over and over with friends, and usually it's the brits and americans who can't understand why most europeans seem to agree with it, even the lefties. i guess they put a lot more emphasis on symbolic individual rights, without stopping to think that while they're getting riled up about a headscarf, their bigger, more important rights are being eroded every single day by things like the patriot act and other laws that make it legal for their governments to pretty much hold anyone indefinitely without a trial, or even charges.
and yet they're baffled by laws such as mandatory ID cards in europe, or the recent wave of burqa bans...
at the same time, i totally agree with people who oppose these laws and who say they're motivated by racism and anti-muslim sentiment. this is undeniable. but i think the important thing is the result.
another thing to consider is that europe for centuries had laws banning face coverings. the only exception was carnival. the result was that more murders were committed in venice during carnival than during the rest of the year, because face coverings do give you anonymity that lets you get away with things you couldn't do if people could see your face.
so yeah, the security concerns are valid as well.
countries had to pass laws making it mandatory for women to remove their face coverings in ID cards, because a lot of them wanted to have their passport pictures taken with their burqas on...