Like everything that the modern social justice cult is promoting, "cultural appropriation" is one of those things that not only is envisioned by the social justice totalitarian regime, but is becoming more and more prevalent as legislation (due to the social justice religion being incomprehensibly virulent, and infecting government after government, and law-maker after law-maker).
"Cultural appropriation" means that white people are not allowed to do or use anything from non-white cultures. Of course such rules only apply to white people, as always, because social justice is deeply, deeply racist, and only blames white people for everything, and wants to relegate white people to subhuman second-class citizenship with less rights than everybody else.
The same rule doesn't apply between non-white people. And, very specially, it of course and naturally doesn't apply to other people "appropriating" white culture.
When these social justice warriors are confronted with that issue, they have a stock response that you will always hear: "What white culture?" Ask the question, and that's the response you'll get 99% of the time. (The other 1% will be some kind of variant that denies white people having any sort of culture.)
They have concocted, and they seriously believe, this notion that white people have no culture and no history of their own, and that they have never invented anything. That the only thing they have done during their entire existence is "steal" from other people. They seriously consider white people, somehow, a species of its own that is incapable of doing the same things as non-white people can, and is able only to steal and copy others.
But of course white people have a long and rich culture in all aspects of life, such as art, culinary arts, architecture, clothing, music and literature.
As an example, so-called "high fantasy" is pretty much solely a product of white people. It's heavily based on old Norse culture and mythology. Most concepts used in high fantasy come from that, such as wizards, elves, goblins, dragons, orcs, and so on and so forth. (In other cultures there may be similar fictional concepts, but Norse mythology is not based on them, and formed on its own. Just because there is some superficial similarity between two things doesn't mean that one was based on the other.)
Tolkien, one of the "fathers" of modern high fantasy, based much of his fiction in Norse mythology. Even his fictional languages were largely based on European languages, especially Nordic ones.
Another big influence in modern fantasy, and many other forms of fiction, is the Greco-Roman mythology. Tons of things are influenced pretty much directly from it. Whenever there are nymphs, fairies, winged horses, bull-headed humans, multi-headed hydras and so on and so forth, they come directly from Greco-Roman mythology.
In fact, much of modern European-American civilization, how society works, and how governments run, is rooted in the ancient Roman society and government. Much of modern art and architecture started from ancient Rome, and it has great influence to this day.
Almost all of historical art existing today in the west, such as paintings and sculptures, were made in Europe, using techniques developed in Europe. Classical music, and music theory, is deeply rooted in Europe.
That white culture.
But, of course, social justice warriors will deny those things being "white culture", because they cannot accept white people having anything of their own. If everything else fails, they will find even the tiniest detail in those things that was influenced by some other culture, no matter how minor and inconsequential, and declare the entire thing part of that other culture and "stolen" from it. And if even that fails, they will find a similarity to something in another culture, and declare that because there is similarity, that's not "white culture". (And of course it never works in the other direction, because reasons.)