I suspect the protestors and the museum staff responsible for the exhibits were of a fairly similar social class; Middle class college educated individuals. Most museum employees who run the show are college educated and it's usually among the privileged who can afford to go to college that I hear bring up cultural appropriation and Orientalism. Those aren't exactly the battle cries of the working class.
Here's where it gets complicated. The Japanese are not an oppressed people. They are an economic and cultural powerhouse who are heavily engaged in trade and cultural exchange with the United States and the rest of the world. Japan wasn't offended by this exhibit and most of them have no problem with westerners wearing traditional Japanese clothing. Most kimono manufacturers would love it if more Americans wore kimonos because theirs is a shrinking market and they'd love new customers. Why is it we prioritize the feelings of a few Asian Americans in this issue? The most common argument I hear is that Asian Americans are, well, Americans, and we should prioritize their feelings. Okay, I'm Americentric myself so I can kind of buy that. Others say it's because of the specific issues that Asian Americans have had to deal with over the last few centuries that the Japanese haven't. And, again, okay, but that kind demonstrates that this is somewhat complicated, no?
And we can relate this to Asian inspired role playing games. Japan, China, and Korea are all too keen on exchanging their culture with the United States. They're not an oppressed people on the worldwide stage. There won't be many Japanese people who care if someone publishes Legend of the Five Rings any more than most Americans care if a Japanese company published a western style RPG.
I'd agree with
most of the points you're making, but I still think this one was fairly obvious, because of the double-whammy of the original picture being from a certain era and the weird disconnected "You can wear it!" thing, which like, only really connects to the art in an odd, Orientalist way. By making a big fuss about the kimono
specifically, rather than just treating as any other article of clothing in a piece of art, it's exoticizing it, and making it a thing to be "experienced". Do you see that? That's the whole "WHOA THIS IS STRANGE AND EXOTIC! HERE SEE HOW EXOTIC! BE EXOTIC!" deal there.
I mean, if they've got a long history of "Here's the clothing from the picture, you can wear it!" exhibitions, then sure, this wouldn't apply as much, but from the coverage I see, that doesn't appear to be the case. The reason they museum chose to do it was precisely because they saw it as "exotic" in a way they don't see the clothing displayed in other art. That pretty strongly supports what the protesters were saying.
Re: class, I strongly disagree. I think what you're actually looking at there isn't "working class people don't care", but rather working class people have to work so hard and deal with so many issues in the US (esp. re health care etc.) that this can't reach high on their priority list. That's
not at all the same thing as "not caring". Middle-class people have enough other problems out of the way that they can take time out to go protest, and they have more connections to the middle and upper class people involved with the university, so their protests have more impact. You see this talking point that "working class people don't care" all over the world, but if they're affected, and you actually survey them about it - they do care, they just don't have time to do much about it. This is really obvious when you work with charities trying to effect social or legal change. A simple example is the class-profile of protestors as you go up the age spectrum - when you're looking at retirement age and older, you suddenly see a bunch more working-class protestors, because now they're free to do it. There's also a vocabulary issue, because education can make it easier for middle-class people to talk effectively about issues.
But being highly-educated doesn't fix not being taught that stuff was an issue in the first place. I mean, you can have your PhD and escape even thinking about that. This isn't new, either, though people act like it is - you go back through the 20th century and there's always a ton of academics pushing outdated ideas and being appalled that their students have the unmitigated gall to suggest said ideas are outdated or harmful. I literally know the sort of people who work at art museums (in the US and UK), who are indeed highly educated and mostly middle and upper-middle class, and I could really easily see this playing out - some 60-somethings in a meeting think this is a wonderful idea, any other, lower-ranking staff who say "maybe don't?" are essentially patronizingly and smilingly dismissed ("young people are so charming but so silly" - young people is anyone under about 45 here of course), and then boom what a shocker.
I think talking about kimono manufacturers is entirely missing the point. If a kimono manufacturer from Japan started advertising and trying to "make kimonos happen" in a big way, whilst they might attract some brief protest, I don't think it would be very convincing or well-supported. These kimonos were specifically commissioned by the museum, not offered by manufacturers or something (or even sponsored by them AFAICT).
Re: Japan and oppressed culture - sure, Japan isn't an oppressed culture in a worldwide sense. It's a cultural powerhouse. And what's more, it's ex-Imperial/colonial power with a history just as dark as much of the West (darker in some cases, but it's also shorter, and that's a separate discussion). It's also very keen on cultural appropriation (mostly from other imperial powers, thankfully). But that makes it a bad example, not a good one. Because usually the issues come up when it is an oppressed culture. Also, the US, specifically, has made Japanese-Americans into an oppressed culture, by, y'know
literally oppressing them in living memory (I mean George Takei - Sulu - was in the camps, for goodness sake). Treating them as alien, exotic, and dangerous in a way that no, other nations did not with people from Axis powers, and also treating them inhumanely. So it behoves museums in the US to be even more careful about anything to do with Japanese culture.
Cultural appropriation is also fairly straightforward, I'd say. People like to try and overcomplicate it with weird corner cases, but conceptually, it's neutral, just a thing that happens (it's slightly unfortunate the term sounds negative, but it wasn't intended do). It's harmful when a powerful culture takes stuff from a weak one, and uses it to benefit people from the powerful culture (often across ethnic lines). The classic example is Native American cultures, where aesthetic styles, dances, and so on were used by white Americans to popularize music or dances or whatever. That's damaging to the culture it's happening to, as it treats it merely as an object for amusement and trivializes it. It's particularly bad when the cultures in question already have an oppressed/oppressor relationship historically. Cultural appropriation from other powerful cultures is obviously not the same sort of deal. Japan and America appropriating from each other isn't really an issue - both do it constantly. It can become an issue when it's not so much portraying that culture, but actively stressing that it's "exotic", "foreign", "so different", "unknowable" or stuff like that. Especially when people are involved and there are stereotypes being applied. (Japan does do a bit of harmful stereotyping of Americans I'd note, and it has had impacts on actual people over there).
Me and my group LOVED OA (assuming you mean "Oriental Adventures", for 1e...right?) when it came out. We played it for about 4 or 5 years more or less straight. Some of the most memorable PC's, situations and campaign that I ever ran or was a part of. 
