NOT all heroes wear capes, and not all potential role models have the arrogance to think of themselves in such terms. But in a world of clickbait headlines and emoji verdicts – where humans are increasingly reduced to good or bad, hero or villain, thumbs-up or angry frown – isn’t it time we admitted that no-one sets a perfect example?

These days, the label of bad role model is more likely to be applied to a young female celebrity who smokes, swears or “displays sideboob” than to a male president who defends neo-Nazis, degrades women and threatens to start a nuclear war. Meanwhile, young men who achieve fame and fortune thanks to their skill at sports are pilloried for binge-drinking, womanising, or generally behaving like immature twits. They should be setting an example, squeal the outraged commentators. Won’t someone think of the impressionable fans?

Well, someone is. Marketing managers are thinking of the fans, and cooking up strategies to mould their clients into brand ambassadors. In this age of terror, chaos and confusion, they’re not just air-brushing images, but entire personalities. Take Kaia Gerber, who was this week the subject of a profile in Teen Vogue’s special “Icons” issue. “Kaia’s unique selling point is that she makes being the good girl the coolest thing you can be,” gushes the magazine’s editorial. Gerber, the model daughter of supermodel Cindy Crawford, wants to be a positive role model for young girls, and “someone their mom would want them to look up to”. She adds: “I don’t take any platform I have lightly. It’s so important to send a good message.”

Of course, the main message this nearly-16-year-old is sending is that she’s beautiful. Sure, she found time at the weekend to retweet Barack Obama, but her 47,000 Twitter followers (and another 1.5 million on Instagram) are doubtless mainly interested in seeing pictures of her looking gorgeous on a beach, or in the woods, or at a party.

I’ve nothing against Kaia Gerber. I’m sure she’s very nice. But as a role model, she’s utterly benign. She’s only a “good girl” in the sense that her carefully curated social media profiles include nothing angry, sloppy, dirty or even faintly controversial. Her role is to look beautiful. That’s it. As regular readers of Teen Vogue will be aware from the magazine’s extensive coverage of #BlackLivesMatter, to be neutral in situations of injustice is to choose the side of the oppressor (I’m not being sarcastic here – there’s much more to this magazine than its title and the above quotes would suggest). So a good role model isn’t merely someone who manages not to do (or get caught doing) anything bad – it’s someone who makes a positive difference.

Not all heroes wear capes and not all nuns wear habits, either. When I looked up Sister Anna Tommasi after reading about her in Wednesday’s edition of The National, I found she looked much like any other retiree visiting a hot country. She doesn’t appear to have a Twitter account, or an Instagram, and I couldn’t even spot a crucifix in the few images I found. But she certainly has young people looking up to her. Lauren Strain – the 21-year-old law student who has followed in the nun’s footsteps by helping free dozens of people from prison in Malawi – is just one of them. She describes Sister Anna as her hero, and credits her with opening her eyes to injustice as well as poverty in Africa. The two first met five years ago during a trip to the country organised by Lauren’s school, St Margaret’s High in Airdrie.

A septuagenarian nun might not seem an obvious role model for a 16-year-old girl, but why not? Strain is at pains to point out that her work helping prisoners apply for bail is “not about white Westerners going in to make themselves look good” or boosting her CV, and if she’s tweeting about it, she’s doing so privately.

Of course, St Margaret’s is a Catholic school, and Sister Anna asserts that she is being directed by God, but that needn’t limit her influence to those who share all of her beliefs. There’s nothing wrong with picking and choosing the qualities and actions we admire in others – indeed, surely this is healthier than swearing allegiance to a single individual, and then defending them as a “problematic fave” if their words and actions fail to live up to expectations.

We need to move away from the nonsense idea that anyone’s perfect, or that public figures can be neatly categorised as the good, the bad and the ugly. Ariana Grande is both the starlet who brought love and joy to Manchester this summer and the young woman who went on a donut-licking spree while declaring “I hate America” two years earlier. Robert Downey Jnr is the untouchable Iron Man to a generation of adoring kids who will be blissfully unaware that he spent decades battling drug addiction. We can’t leave it to the likes of Miley Cyrus and Justin Bieber to set an example to kids, and we shouldn’t demonise celebrities for tumbling off the pedestal on which a capitalist society has foolishly placed them. When casting around for people to exert a positive influence on the youth of today, surely the best starting point is to look in the mirror and ask: could it be me?