'Cultural-appropriation' is another one of those half-assed, ill-considered concepts that middle-class 'liberals' thought up over wine-fuelled dinner parties and never bothered to think through.
True progressivism is about interaction, cultural exchange and mixing - the exact opposite of dividing, pigeon-holing and telling people they are this or that and shouldn't try to be or appropriate anything else. Besides, where does this ideology fit with the other current vogue among 'progressives' for self-identity and self-expression? And, as NV pointed out, who the fuck decides what belongs to one culture and not another?
Also, is cultural appropriation a one way ticket? Are young black women being told by middle-aged white people not to straighten or dye their hair, or wear extensions?