It's a thing in social justice circles. Just did a college class on Post-modernism, so we covered all that stuff (had two lecturers, one cool one and one uptight retard PC type, who talked about how all belief systems were relative, and open to critique, which was cool, except as soon as you gave a perspective that wasn't in line with his agenda on some social issue he'd turn mega-passive-aggressive. So it's like "all the traditional thinking has been overturned by post-structuralism. But don't you little assholes question a single thing I tell you is certified truth").
For "cultural appropriation", one example I read about is for kimono manufacturers in Japan. The industry is gradually going broke because few of the wealthy Japanese these days buy expensive kimonos like they used to. So a group of Kimono manufacturers set up a cultural exchange with museums in the USA, and those museums had a thing where they did kimono fittings for visitors. Cue: Asian-American college kids picketing the whole thing protesting about "cultural appropriation", forcing the thing to be shut down. Very few of the protesters were Japanese-Americans however, and almost no Japanese understood why it was considered racist.
But when you think about it, is there really much difference between protesting people in America wearing kimonos because racism, or protesting kimonos because you're racist. Both are trying to prevent cultural blending, but for opposite stated reasons. Both associate race with a cultural artifact, and say you should stick to cultural artifacts that are appropriate to your race. I'm skeptical of the value of screaming about "cultural appropriation" in this manner. Like that asshole lecturer who uses "political correctness" to dominate other people's viewpoints, this sort of angry activism could be part of a movement to project social dominance over the public sphere of a particular social class. After all, they completely trampled over the thoughts and feelings of the group they're purported to be "protecting" from cultural appropriation, which just doesn't sit well with me at all.