After Caroline Flack’s death, the #BeKind hashtag was retweeted millions of times, its message transferring, in phrase anyway, from the internet to real life, appearing in bookshops and on cupcakes. One clothing brand raised £100,000 for the Samaritans by donating a single day’s profits from its “Be Kind” T-shirts. And so the idea of kindness rinsed the country like a cool wash – a reminder, a plea, a bellow from the kitchen.

I have been thinking a lot about kindness. A couple of years ago, as the concept started to be repeated more and more as a buzzword akin to mindfulness, with self-help books on the subject proliferating, and the TV and film industries announcing their intention to promote it with their programming, I investigated kindness for this magazine. The research took me back to the “happiness industry”, often criticised for displacing attention from the causes of unhappiness. The difference between happiness and kindness, I suggested, was that the former was passive, but the latter active. But since the rise of the hashtag, I’ve started to question this.

A number of things have spurred my questioning. One was the Daily Mail columnist Sarah Vine, who, upon the prime minister announcing last week that his girlfriend Carrie Symonds was having a baby, urged her Twitter followers to “be kind to the pregnant lady”. Vine’s kindness to pregnant women however, was memorably lacking when Meghan Markle announced her first child, with pieces on “bump boasting” and the problem with Markle’s birth plan. Apart from the comic hypocrisy of Vine’s message, one so loaded with self-interest and politics the original sentiment has almost dissolved, like nachos, soft and flannelly under their heated cheese, it vibrates with the proof that when scrutinised, “kindness” is not one thing. That it is allowed to shape-shift according to voice, time, audience and intention.

Perhaps the most clear evidence of this came in the form of a photo shared online of protestors holding banners outside an abortion clinic in London. I’ve seen plenty of these groups in the flesh, but the news that such protests are rising reignited my fury. Thirty eight hospitals, GP surgeries and clinics in England and Wales have reported experiencing anti-abortion activity in the past 18 months; eight of these protests are new, with Bpas (the British Pregnancy Advisory Service) saying protesters are taking “advantage of the insufficiency and incompleteness of the existing law to impinge on women’s access to care”.

Anti-abortion protestors believe they are shouting at scared girls to be kind

Government indifference to the enforcement of women’s legal rights has led them here, with their blown-up photos of foetuses and their laminated signs about Jesus. Emboldened, a Texas-founded campaign called 40 Days for Life has encouraged more to assemble outside abortion clinics throughout Lent, some filming women entering, some pushing leaflets into their cars that say abortion “causes breast cancer and increases the risk of suicide”, and some with microphones calling women murderers.

My simplest response (and one that I croak from under the weight of an eight-month foetus, more aware than ever of the horror implicit in asking a woman to carry and birth a child she knows she can’t care for) is that if you don’t like abortions, don’t have one. If you’re a man, and don’t like abortions, make sure you don’t knock anyone up unless you’re sure you’re able to love and support a kid for the rest of your life. But as simple as it seems to me, it must seem even more straightforward to the protestors, who believe they are acting out of care to the unborn foetus. Though their actions appear needlessly cruel, I’m sure many of the protestors believe they are shouting at scared girls because of love, because of tenderness. To be kind. Brrr.

Which leads me to think that a campaign that asks individuals to “be kind” is destined to fail. Creating a kinder culture relies on a shared motivation, well beyond protecting each other from online bullying. Kindness, in this context, is code for empathy, an action far harder to perform, because it relies on putting yourself in a stranger’s shoes, and imagining their feelings, their incentives, the weight of their rotten dad’s rotten faith. For all the flattening togetherness of hashtags, we’re not all the same, and we don’t all have the same moral codes, the same ideas of what kindness entails. So to urge our own concept of kindness on a disparate group of strangers is to invite disappointment.

“Be Kind” is a phrase acceptable only for children and hashtags. Because the longer version, the chewier, more complicated version that lies beneath, the one that acknowledges and attempts to change the structures of our societies, both on and offline, so that we are all understanding of and enriched by other people’s wellbeing, requires thought, compromise, hard work and, occasionally, just shutting up. And that sentence by itself would struggle to fit on a T-shirt, let alone a cupcake.

Email Eva at e.wiseman@observer.co.uk or follow her on Twitter @EvaWiseman