Die, Die Harley, Die
Admittedly, the whole idea of reinventing Harley Quinn as Yolandi Visser – a gamine cooing over a tattooed gangster – is pretty brilliant, and Visser's video convinced me that the Suicide Squad designers indeed borrowed from Die Antwoord (though it's not as though Yolandi Visser was the first to wear multiple-watches on one arm, a look spotted around the time Die Antwoord's album first came out). But none of those small similarities are essential to Die Antwoord – or to Suicide Squad. The whole thing reminds me of Lady Miss Kier's lawsuit over Space Channel 5, where the court found that the similarities were far outweighed by the differences (and, significantly, that you can't claim appropriation, in a legal sense, while also saying your style changes constantly.)
But forget the legal sense. This isn't a court of law. By copying Die Antwoord, Suicide Squad made itself a little cooler, at the cost of making Die Antwoord a little uncooler.
In his 2000 book Nobrow: The Culture of Marketing, the Marketing of Culture John Seabrook argues that we no longer live in a world of "high" vs. "low" culture; now the DMZ lies between mass culture and subculture, as consumers "construct an identity out of a collective" of products. Investments of identity in subcultures are "riskier but potentially more lucrative", since popular opinion of their value can shift; but invest too much in the mainstream, and you're just one of the crowd.
Subcultural art is not necessarily better, in any imaginable qualitative sense, than mainstream art, and it certainly doesn't have to be more authentic. (Talking about Die Antwoord's "authenticity" misses the point – they're art students LARPing as South African gangsters, keeping Shatnerian straight faces as the parody mounts.) On one level, even their complaint that Sony stole from them what they themselves stole from street culture is just another parody. But on another …
On another, Sony stole the value of being a Die Antwoord fan. Where's Batman when you need him?