Yes, the cultural norm changes over time. The cultural norm in Europe, however, despite fashions, facial piercings, risque clothing at Royal Variety Shows, bald women, is the uncovered face. It is not a fashion. It is not just the current norm: it is the pervasive cultural norm. It is to do with communication, acceptance and integration, and it is most certainly double standards to allow different observation in different societies.
I have issues with the way many of the countries I've visited/lived in treat women. I have had discussions (with "locals" about whether I am allowed to judge: whether to act: whether to interfere, which it would be, as an outsider. You cannot assume that the ethos is "we are better than them". I don't even know what you are talking about here: private views may be held but the common, publicly expressed view should be that of respect. Through respect, understanding may be gained.
Through all this I have understood and respected that there is little to be gained by hostility and defiance of the cultural norm.
Again, I have seen no acceptance, understanding or attempt at understanding of this cultural norm by veil wearers.
Why is that question relevant?