Cultural appropriation is the adoption or use of elements of one culture by members of another culture.But of course it only applies to white people. Read the whole thing. They have some examples of appropriation that are from white to white, but the important issues all revolve around white appropriation of non-white cultural elements. Thou shalt not wear a Halloween costume of an Indian or Geisha or whatever. It is a form of colonialism.
It is a fundamentally silly idea, but when applied to music, even more silly. Yes, there are an awful lot of very interesting influences coming from world music and popular music, but the whole foundation of music, the harmony, the counterpoint, the very notation to write it down, comes almost entirely from France and Italy between eight hundred and a thousand years ago. Are we going to say, "no more triads, we want our harmony back!"
Of course an even more biting criticism has already been unleashed: if you think that cultural appropriation is wrong, then please stop using vaccines, antibiotics, the Internet, smartphones, computers, jets, the internal combustion engine and, heck, electricity. These are all the creation, invention and discovery of Western European and North American white people.
Our envoi almost has to be something by Léonin the composer, in the late 12th century, of the first written down polyphony: