Cultural appropriation - is it ethically wrong?

The racial alignment of ancient Egyptians is, academically, a widely debated subject, but it's not exactly a 'hard sell' to say that they were a black society - there's a whole widely researched hypothesis around it (Black Egyptian hypothesis - Wikipedia, the free encyclopedia).
DNA analysis shows the ancient Egyptians didn't have sub-Saharan genes:
The team then compared the ancient mummy DNA to the DNA of both ancient and modern people in the same region. It turns out that, on a genetic level, the ancient Egyptians aren’t so different from modern people living in the Near East. In fact, they have more in common with those in the Near East than today’s Egyptians. For example, the mummies didn’t have any DNA from sub-Saharan Africa, whereas about 20 percent of today’s Egyptians have sub-Saharan genes. Study lead author Johannes Krause told Science that the modern-day variation might be because either the spread of Islam or more trade increased contact between the different parts of Africa.
Source: Mummy DNA shows that the ancients don’t have much in common with modern Egyptians (30. May 2017)
 
A little funny exchange from the Internetz, possibly relevant to this topic:
Ms Del Rey responded calmly, saying that she was "never pretending to be vegan", just that she didn't like the taste or texture of most meats.

The unnamed vegan was not satisfied and told Ms Del Rey that, "Tofu is strictly for vegans or vegetarians. You are basically admitting to appropriating from us and stealing from us for your own selfish use."
More: Vegan roasts tofu eater in furious online rant over 'appropriation' (12. Jan. 2018)

"Angry vegan" would probably explode with anger if they knew that tofu had been "appropriated" by huge numbers of non-veg*ns in China for hundreds of years :)