“When privileged people make money off the knowledge and practices of people who have been oppressed for centuries and also when they do not recognize their struggles or give back to the community from which they are benefiting.”
But in reality, “cultures” aren’t owed anything from the people who use *their own* skills to create things or express themselves. The moment an idea or expression is released into the public domain, it is public property. The marketplace (not cultures) decides whether that idea is good or bad, appropriate or not.
This idea that someone cannot use/create/profit (etc.) from public domain material is not only unenforceable, but oppressive in and of itself. It runs completely contrary to freedom of speech and expression.
If you are offended by the products or services someone is offering, for any reason, you should boycott them. But the fact of the matter is that consumers respond to quality and quality alone… And if white people are creating quality Henna art (or Mexicans are cooking quality Chinese Food, or British people are selling quality Italian-style art), then consumers are going to procure these things regardless of the level of offense you take to it.