Your costumes are very beautiful!
As for the offense, I really don't get that campaign. Of course when you're a minority in a country where you're discriminated, you don't want to be mocked or reduced to a cliche on top of it. So I kind of get that for, say, American Indians, it is an issue to have their traditional attire made into cheap and ugly caricatures.
But not all things that are typical for a country are offensive. I'm German, and neither Oktoberfest nor Nazi stuff is what I am, but someone dressing like that in a US Halloween? Extremely poor taste in case of a Nazi outfit, and you bet I wouldn't want to think people that represents Germany, but in my opinion, the people in such a costume mainly would embarass themselves, not me.
If you had put all that effort into a stunning Oktoberfest couple outfit, I'd probably roll my eyes for a second, and then congratulate you to the great job you did on it. And probably be a bit jealous on your skills
As for your gorgeous Japanese, costumes, I don't see the insult in making a beautiful costume that's inspired by someone else's beautiful traditional clothing. After all, you don't wear this because you think it's a joke.
It'd be interesting to have a Japanese craftster's opinion on this, I'd really like to hear that.