Appropriation: ugly word. It has overtones of the bailiffs kicking the door down and marching off with the family's meagre possessions. Oh no, at least leave Tiny Tim his crutch!
In fact when a culture takes something from another culture it only does so virtually. The thing is still there for the original culture to use. No theft has occurred. The original culture hasn't lost anything.
Cultures trade their creations all the time. It happens whenever a book is translated, whenever an English film director goes to work in Hollywood. It's generally accepted that great works of art are transnational. Nobody suggests that only Greeks should act Sophocles or only Germans play Beethoven. We'd laugh if they did. Or call them fascists.
Cultures refresh themselves by exchange. Over the past century and a half there was been intense traffic between Japan and the West- two very different cultures falling over one another to help themselves to one another's bits and pieces. No-one thinks it awful that Kurosawa stole from the Western to make his Samurai pictures or that Hollywood repaid the compliment by turning Seven Samurai into the Magnificent Seven. Van Gogh learned much of what he knew from the Japanese print makers. The Japanese think he's wonderful.
Contemporary popular music is a stew of influences- African, African American, European, Latin American, Jewish. The Beatles accessed black American music through Elvis and Buddy Holly, added a bit of music hall, a bit of Northern English working class attitude, a touch of Lewis Carroll and the Goons- and sold it back to America. Try unpicking these things and you'll give yourself a headache.
There's no such thing in our globalized world as a culture that's pure, untouched and wholly indigenous. Well, maybe in the Amazon rain forest, but nowhere else- and even those guys mostly have radios and laptops now. The person who annoyed wyrmwwd was objecting to the appropriation by the West of the Mexican Day of the Dead. Really?That's a culturally pure product that no-one outside Mexico should touch? I don't think so. It's a mix up of Aztec and Spanish traditions- with a bit of Africa mixed in- and very closely related to the Dance Macabre which is a pan-European phenomenon.