Normally I would agree with you but wearing something that conceals somebodys identity is unacceptable. Wearing a Halloween mask once a year is hardly comparable.
But a Halloween mask does conceal someones identity. So I don't see how you can say "oh but that is fine" just because it provides you with a difficult question in your beliefs. What about cosplayers who often have masks / items that hide their face as part of their costume? Also, a side question here, why the hell do you think you have the right to know the identity of a random person in the street? You don't. Why do you even care? I don't pay attention to 99% of the people I pass when I am in public so I don't see why it even matters!
Would you say it's unprovocative to wear clothing or sing songs signalling historic differences, as happens in Northern Ireland, or provocation is in the eye of the beholder? How about Nazi uniforms? Is it the sign of a civilised society not to rise to provocation, or are there no limits on the freedom to express personal views through clothing?
1 - Clothing is totally differing to singing songs.
2 - There is a massive difference between banning something because it has historical links to something nasty and banning something because either you do not like it or because you can't see their face. In any case, I think people should be able to wear what they like. But they should not be immune from comment about what they choose to wear. So if someone does decide to wear a Nazi uniform, then fine - but they shouldn't complain when a national newspaper prints a photo of it on their front page! With the Burka, I am happy for it to be criticised. I actually think it is quite an interesting cultural topic, do we dislike it because of security / hiding someones face, or is it more simply because it is totally alien and different to us (which is what I think). But what I disagree with is just saying "we are going to ban it" - what does that actually achieve, apart from putting you on the wrong side of a section of the population?