Minorities face real problems in the US. What a waste of energy to harangue a teenager for wearing a Chinese dress.

When is a dress just a dress? Remember those photos of the little cocktail number that looked blue with black lace to some and white with gold lace to others when they were in fact the same frock? American teenager Keziah Daum now possesses a prom dress with similar magical properties, and it’s landed her in hot water with culture pedants.

The attraction of the qipao (“cheongsam” in Cantonese) is obvious: a sexy, figure-hugging sheath of silk with a high mandarin collar balancing a va-va-voom flash of leg via a thigh-high slash. Its beauty, however, turned into a curse when photos posted on social media of her wearing her beloved vintage find made her a target for tens of thousand of tweets accusing her of cultural appropriation. That’s one heck of a fashion crime.

The original complainant’s instinct – to draw a line at a time when Chinese people are under siege from Trump-inspired China-bashers – is understandable, but in this case, completely mistargeted. If anything, the qipao represents power and class, not race, and certainly not the culture of some exploited underclass.

The qipao’s history is said to have originated with the Manchu Qing dynasty, when members of the Han population they ruled were forced to wear a loose version of the one-piece instead of their own traditional clothing. Created in Shanghai in the 1920s, when warlords ran vast swathes of republican China, the slinkier form of qipao was a fashion favoured by one ruling strand of Chinese society that we associate with Chiang Kai-shek’s nationalists, who fled to Taiwan when the communists won their revolution in 1949 and ditched the bourgeois qipao for Mao suits. Some even detect a western influence in its hybridisation, meaning the current outcry could be compared with taking offence because someone in Asia wore a tuxedo.

At its core, the identity debate is about power: who has it, who’s lost it and who’s chucking it around with abandon. This is hardly a case of a white American dressing up in a fringed chamois tunic with a feather headdress, mocking the indigenous people their antecedents almost wiped out.

At least Keziah wasn’t tip-toeing around to mimic bound feet in a play set a millennium before foot-binding became a thing in China, as in perhaps the most absurd example of cultural appropriation I’ve witnessed. In More Light at London’s Arcola theatre several years ago, seven white actresses played Chinese concubines buried alive (allegedly) with China’s first emperor, Qin Shi Huang, who died in 210BC. Wearing kimonos (Japanese) and sticking chopsticks in their hair (!), this was a prime example of badly executed appropriation. Unlike Keziah’s appreciation.

When cultures meet and mingle, they inform and enrich each other. I can wear tartan, wear pyjamas, knock up a curry, curl my hair, cry along to the blues and dance to funk. I know the difference between a schmuck and a schlemiel. I’ve sat shiva for a friend’s father. I love gefilte fish. Does this make me a cultural appropriator?

The whole cultural appropriation debate is in danger of being turned from a defence of minorities under the colonialist cosh into a lazy substitute for real political power. How has it degenerated to the extent that we’re now on social media mobbing teenagers whose only crime is to consider a Chinese dress beautiful? Qipao-gate this isn’t.

With President Trump and his acolytes pumping up yellow peril fears around China, and his trade wars threatening to slip into hot wars, the last thing we need is this trivialised pastiche of serious debate. Minorities have precious little ammunition with which to challenge tribal juggernauts. Don’t waste what little cultural and political firepower we have.

Keziah was neither stealing power nor claiming ownership. And she looked lovely.

• Anna Chen is a performer, writer and blogger who writes and presents programmes for BBC Radio 4. Her blog, Madam Miaow Says, was shortlisted in the 2010 Orwell Prize for blogs