All these divisions are entirely artificial. No-one owns a culture any more than they own a language. It also conflates cultural assimilation with problems of racism and seeks to solve racism with more racism, by creating rules for what people of a so-called dominant/oppressive group may do, treating them not as individuals, but as mere representatives of that group. Erecting a form of cultural apartheid based on skin colour and nationality will make the world an uglier, more bigoted place. It will not protect anyone nor will it solve any of the issues it seeks to redress. In short the concept of cultural appropriation is one of the worst ever invented.