"Of course appropriation does exist; consider the white college girls who use indigenous war bonnets as trendy, pseudo-bohemian accessories."

Of course it exists, but I'll humbly point out that culture rises up from the bottom, it doesn't get imposed from the top. We may not always like where culture takes us, because the modern trend is active disdain for history, for tradition, for the sacred, etc. but that also has some pretty valuable lessons around our human desire to extoll history, to cling to tradition long past it's usefulness, to emotionally charge ordinary items as 'sacred'. Culture is fluid, not static.

One of the interesting intellectual conundrums in social justice is religion, in fact. I've been witness to discussions where self-admitted atheists pound away on Christianity and Islam like prize fighters, but then flip on a dime to get angry at college kids for dressing up like natives for Halloween. Apparently, only SOME sacred traditions deserve respect and protection.