I think there is a confusion between blackfish and following Black popular culture.
Urban Black culture is and always has been popular among young people. I don't know why, perhaps because it's seen as edgy.
Lots of white children copy the styles in the same way that some white children become goths or punks.
Clinging on to a fashion, which for many the hip hop style is, is just part of growing up and finding your identity.
Personally I think the Kardashians get alot of flack for using black styles to make money. But it seems more to me that they fetishaise black people and culture, possibly because they are Arminian and felt they never fitted in with their white peers. I'm not saying that's ok, just my take on it. I suppose as it then gained them popularity they pushed it further. But Kim only seem to really start to try and look black after she got with Kanye.
When we accuse people of copying black culture, it's usually hip hop/rap, Urban type culture we refer to, not carrabian or African culture. So arnt they just copying popular culture? And imitation is the biggest form of flattery.
I don't think anyone should tell anyone how to look. Maybe we should address the discrimination Black women face, rather than tell young white girls they can't copy their favorite black popstar or dress the same as their black friends.