Agree on your comment about the more dangerous aspects of political correctness, but this is separate from critiques about cultural appropriation in fashion.
Have you read this Time article by Scafidi? It's probably the best, most sensible thing I've read on cultural appropriation in fashion, and directly touches on the use of Native American imagery
Also, Zizek is really insufferable.
Well cultural appropriation (I'll use CA from now on) really should be discussed using more interesting concepts like Rancière saying the crux of representation is who gets to say what and when (who gets to represent/who speaks and "where he is speaking from"-Lacan-), at least it addresses the current common wisdom that "images" are available in such a massive form that they're drowning discourse (a really foolish idea). The problem with it is I don't see how CA builts on that with anything but confusion. It is an ok concept for a blog post or a discussion (within reason) but too weak to function outside of that as it is basically just borrowing from a low power group in a way that the speaker thinks isn't respectful. It is also often yielded as an ideological bludgeon against what is, at most, a venial cultural sin. There's also the enormous respect many of the left give oppressive traditional cultures merely because said cultures are now themselves oppressed/minorities/disappearing. You know like the nice Tibetan traditional cultures where everything was owned by the clergy and you had to give them sons and that kind of shit?
Zizek is hilarious, especially when he's doing his comic duo with Badiou (the wise man and the fool). Some of his books are serious business, other are pop culture fun stuff.