There are few things more terrifying than being stripped naked in public.

That’s why anxiety dreams so often do away with clothes, and nudity tends to be reserved for people we trust. Going starkers in front of strangers is, then, a brave move. But can it ever be an empowering one?

This week Little Mix became the latest in a long line of female artists to take their clothes off supposedly in the name of feminism, with a naked photoshoot to promote their single Strip. So far, so old hat. But the twist on the perennial theme of getting naked for free publicity is that the song is about dealing with toxic social media; and in the picture their exposed flesh is covered in scrawled insults used about the band online.

“Ugly” is inked on an upper arm, “slutty” just below the knee, “flabby” on the curve of a buttock. It’s less sexy or titillating than arresting and sad, faintly reminiscent of those wallcharts that hang in old-fashioned butcher’s shops diagramming the various cuts of meat. Little Mix were in their teens when they emerged from the celebrity sausage machine that is X Factor, and have been marinating in this kind of pitiless scrutiny ever since. But teenage girls don’t have to be famous any more to be bombarded with this stuff, designed to shame and intimidate. They just have to be female, and on the same social media as all their friends.

If taking your clothes off in public is such a powerful act, it’s strange that men don’t do it. Boy bands generally keep their trousers on, while girl bands invariably perform, as Little Mix do in the video for Strip, in little more than their knickers. It’s young female actors and models at the start of their careers who must routinely undress, while those at the top get body doubles and modesty clauses. The reason Marks & Spencer found itself pilloried this week for window displays showing male mannequins in smart suits next to female ones in their underwear, respectively captioned “outfits to impress” and “fancy little knickers”, is precisely because being stripped to your pants while everyone else is covered tends not to be a power move.

Piers Morgan missed the point about Little Mix’s publicity photographs. Photograph: Ken McKay/ITV/REX/Shutterstock

But for all that, Piers Morgan was somewhat missing the point when he suggested that Little Mix should stop using sex to sell records. I understand why parents of younger fans long for just one female tweenage idol who keeps their clothes on. But it’s striking how this has resonated with a slightly older demographic using the hashtag #stripwithlittlemix to say that this was something they’d needed to see; a debate about what precisely makes them feel so insecure and inadequate, what drives them to cut and starve themselves, or to spend hours cropping their perfectly normal-sized thighs out of photos. It wasn’t about sex for them, but shame and ways of overcoming it.

My own feelings about this started to change when the writer and mental health campaigner Bryony Gordon ran the London marathon last year in her bra and pants to make a point about body acceptance. Gordon, who features in Little Mix’s video alongside the anti-FGM campaigner Nimco Ali and other women picked not for their looks but for their views on body shaming, is a gloriously unabashed size 18 who gleefully described the pleasure of running with her flab “jiggling jollily”.

So many women are intimidated out of jogging in public or joining gyms because they don’t want to be feel judged in their Lycra, and Gordon’s big black running knickers were a genuinely empowering response to that – an eye-catching way of showing that fat doesn’t have to mean unfit, and that it’s ridiculous to let unnecessary shame come between women and their physical or mental health. She’s fit enough to run a distance that would kill some people, so who are you to pass judgment on her body from your armchair?

But the question of taking your clothes off in public isn’t always so cut and dried. The general rule of thumb as to when it is and isn’t empowering is perhaps that it should always be enthusiastically voluntary, and that it’s not really a political gesture if it could be made equally powerfully from inside a cardigan. All those pictures of a 16-year-old Kate Moss half naked are more of a reason for feminism to exist than a feminist statement; it was only years later that she admitted to crying in the toilet on shoots, after being told that girls who refused to take their tops off didn’t get booked again.

At the other end of the spectrum is the liberating thrill of skinny-dipping with friends, the briskly levelling experience of saunas, and the middle-aged Women’s Institute stalwarts immortalised in the film Calendar Girls, who by posing (strategically) naked for a charity calendar neatly subverted the idea that older women’s wrinkled bodies are somehow too gross to be seen.

Kim Kardashian shooting naked selfies in the mirror, meanwhile, hovers awkwardly in the middle: while it would be nice to see a woman breaking the internet with her brain not her bottom just for once, the world has already seen her naked in mortifying circumstances thanks to a leaked sex tape, so there’s perhaps an element here of taking back control. Blackmail doesn’t work on victims who are willing to let their guilty secret come out, and perhaps there also comes a point where the only way of countering body shaming is to flaunt the thing that is supposed to be so shameful.

Little Mix should have thought harder, perhaps, about the risks of encouraging their younger fans to post pictures on a hashtag about stripping. But it’s funny how it’s always the young women half-naked on stage or on Instagram who end up being shamed for it, not the men making fortunes off the back of their exposure in music, film and media. The message of the song is that women won’t be shamed, that bodies should be enjoyed with all their supposed flaws. The reaction to it serves in some ways as a reminder of why that still needs to be said.

• Gaby Hinsliff is a Guardian columnist