So one can wear a head scarf, but not if it is connected to islam? What about a kippah? A tichel aka "jewish head scarf". Or what if i want to wear a mitra as the president of the european commission?
They did not "ban head scarves", they ruled that /if/ wearing religious symbols (and it gets interesting at necklaces with crosses) is not allowed, /then/ scarves fall under the rule, as well.
The ruling is more or less a nothingburger, because if you're against that restriction you're against the blanket ban in the first place, not so much against this specific interpretation. It's only interesting for legal doctrinal reasons.