Some of us were troubled when Julius Malema said in his press conference on Monday that he wouldn't allow South Africa to be sold over a plate of curry. He was talking about the Guptas, and it wasn't his characterisation of that family as scoundrels, scumbags and corruptors that was troubling, it was the use of the word "curry".He had just ejected ANN7 reporters from the briefing, saying he couldn't guarantee the safety of journalists working for the Guptas, which is a phrase that should always cause chills, given how regularly it crops up whenever a group is threatening a more vulnerable group with violence. Now there's an obvious problem with threatening individuals, and another with threatening journalists, even if those journalists are a paltry, craven and shamelessly lickspittle shower of incompetents and malfeasants, but there's another problem too.The Guptas are Indian. Indians eat curry. Malema, it seems fairly undeniable, was yoking a veiled threat of violence to a shorthand for a specific ethnicity. The problem with the Guptas, Malema was implying, is not merely that they're an incubus squatting on the chest of South Africa, but also that they're Indian.We shouldn't be surprised by this - threats and ethnic slurs go hand-in-hand with Malema's brand of exclusionary nationalism and his idiosyncratic interpretation of good democratic practice - but perhaps we should be troubled. Should the Guptas go? If so, it's because of what they do, not who they are.A number of people expressed words to this effect on Monday, and a local commentator begged to differ. She wasn't offended by the curry comment, she said: Malema wasn't being anti-Indian. That's fine, opinions differ, and ordinarily I'm all in favour of someone not being offended. I'd cross the street to shake the hand of someone not currently in the process of taking some or other form of offence. But she went on. Non-Indian people being offended by the curry comment, she said, were guilty of cultural appropriation.Cultural appropriation is one of those crimes that seems increasingly easy to commit or to spot. It's the charge of using the forms and tropes of another culture without due respect. That sounds reasonable, but it becomes more complex when we look at specifics.In Ottawa recently a university yoga class was cancelled over concerns about cultural appropriation. Yoga, it is argued, is a classic case of the West exoticising and diluting an ancient Eastern tradition, and taking it over as its own. The same has been claimed about white American college kids wearing sombreros to sports events.It's easy and rewarding to make fun of this. As Michelle Goldberg, biographer of the female yoga populariser Indra Devi, writes, asana-based yoga is not an ancient practice of spiritual poses, but rose from the Indian nationalist movement's ambitions of developing a distinctly Indian version of physical fitness. The asanas were concocted from a combination of medieval tantric practices, wrestling exercises, British army calisthenics and Scandinavian gymnastics, and the system was called "yoga", a word that previously meant something very different.Similarly, the Mexican sombrero came to Mexico from Spain, who themselves may have appropriated it from 13th-century Mongol horsemen. National cultures and cuisines are always amalgams of influences from neighbours, visitors and trading partners. The Dutch tulip comes from Turkey and came to Turkey from the plains of Asia minor and Iran. All culture that's worth anything is a living organism with semi-permeable membranes, growing and breathing and interacting.Taken to absurd extremes, the cultural appropriation police insist on halting evolution, trapping their chosen cultures inert inside a snow-globe. They want an impossible world in which cultures keep to themselves, not mixing with the other cultures who live down the road. This doesn't sound like a society we'd want to live in.But I'm not rubbishing the idea of cultural appropriation. It's an important tool for identifying and diagnosing the epistemic violence that can occur when one powerful culture absorbs and neutralises another. It's such an important tool, we need to be thoughtful about how we use it. The same is obviously true of racism.When the ANCYL characterised the Zuma Must Fall banner in Cape Town as an inherently racist act, without knowing who posted it or why, and when the vigilant scourges of Stellenbosch didn't pause to check whether the recent case of blackface mightn't be purpleface ("Who's inside Barney the Dinosaur? Better not be a white woman!"), they weakened the valuable tools they were using.Racism is important, and the violence of cultural appropriation is important, and it's precisely because they are that using these words as weapons to get out of a tight spot in an argument reduces them and diminishes the conversation around them. Words matter. That's true no matter who is using them...