Recently, a provocative hashtag, #EndFathersDay, was copied all over Twitter. The hashtag was taken up at first by feminists who thought it was a good idea, but then much more so by men who thought it was an outrage. Even more provocatively, the hashtag #WhiteWomenCantBeRaped was copied all over Twitter, too.

Both, it turned out, were hoaxes. Over on another internet service, 4chan, users exchange views anonymously, and untraceably. It is a formula that invites extremes of bad taste and adolescent malevolence. Not so long ago, some 4chan users cooked up a plot that they called ‘Operation Lollipop’. Over time, the 4chan hoaxers created false Twitter identities with stereotypical profiles – like NayNay Thompson, a self-described intersectional feminist and Marxist – and started tweeting parodies of radical tweeting – parodies that were nonetheless happily taken up by ‘real’ Twitter activists.

The 4chan hoaxers’ realised that some hashtag activists would be daft enough to take up slogans that were obviously absurd. The 4chan gang knew how Twitter worked. They had seen that it was a platform that thrives on controversy and snap judgments. They had seen, too, that it was particularly sensitive to arguments among those who see themselves as oppressed. On Twitter, radical feminists have been split apart by a series of acrimonious debates. Not too long ago, a group of radical feminists were re-branded as ‘trans-exclusionary radical feminists’ – TERFs – because they barred trans-gender men from entry to their women-only meetings. Before the newly trans-friendly feminists could enjoy their moral superiority, they too were called out for being racist, when #SolidarityIsForWhiteWomen trended. Male leftists were mocked as so many ‘brocialists’ and ‘manarchists’; men who wanted to be allies were dismissed as ‘white knights’. In the US, columnist Sarah Kendzior trolled the left-wing magazine Jacobin, saying, falsely, that it had initiated a campaign of rape-threats against her.

The TERFs complained that ‘TERF’ is itself exclusionary and ‘othering’. The white feminists pleaded for everyone to be kind. Sam Ambreen called everyone a racist – and added #KillAllMen. So it seems the parody launched by 4chan was nowhere near as ridiculous as the reality. The extreme postures people adopt on Twitter are in inverse proportion to their importance or effectiveness as activists. People tapping away at their phones are not involved in building a social movement, and so they do not understand the need for collaboration and compromise. They are more interested in the dramatic effect of striking a pose and denouncing someone else.

The endless divisions and ratiocinations of feminism on Twitter, the subdivision of the movement between women and men, between radical feminists and liberals, between ‘sex-positive’ and ‘TERF’, between Women of Colour and ‘White Feminists’ – all of these are the brittle signs of an association that is mired in theoretical antithesis. ‘Theoretical antithesis can be resolved only in a practical way, through people’s practical energy’, Karl Marx once mansplained in his Economic and Philosophic Manuscripts. ‘Their resolution is therefore by no means only a task for knowledge, but a real problem of life’, he added. The Twitter churn spins around like a cog that has become disengaged from all others to turn freely, but pointlessly, on its axle.

Hoaxing is a great and venerable tradition. The French ‘Situationist’ group once snuck into a small town and overnight chalked ‘Don’t drink the milk’ all over the walls. The following day, milk was left untouched. Later, after a threat of lay-offs, the local dairy came out on strike. The Situationists were thrilled. Later on, the Situationist leader, Guy Debord, wrote a fake handbook for the destabilisation of the Italian parliament, as if written by senior civil servants in Italy, with plans to plant bombs and blame them on radicals. He even affected a classical Italian literary style – and the booklet, once leaked, was reported in the press as an actual blueprint for a right-wing takeover. As he knew, there really were such plans, and the hoax helped to get the issue talked about.

At the high-point of the postmodernism craze, a frustrated physics professor, Alan Sokal, submitted a paper to a journal called Social Text that set out his ideas for a postmodern school of physics. When Social Text published the paper, Sokal announced the hoax and showed up the unreliability of postmodern academia. When Sokal’s hoax was reported, many radicals were outraged. Some, like Judith Butler, claimed that the parody itself was a reactionary, ‘sadistic’ move. On similar grounds, Plato thought that art was dangerous because it was a lie. But humour, at its best, works to subvert fixed attitudes; it is a motor of change. Laughter comes with the release of tension. Where things are stiff and mannered, we are all ready to burst out laughing, like in a difficult maths lesson, with the teacher warning us that the next person to laugh will be sent out.

The defenders of Twitter’s hashtag activism have reacted angrily to the 4chan hoaxers. Why? The hoaxers’ fake tweets and parody hashtags are all part of the fun, too. The ‘genuine’ hashtaggers complain that Operation Lollipop was sexist in its inspiration – which is no doubt true. But even bad motives can have positive outcomes. And you would have to take into account the recent survey of misogynist trolling that found as many women as men were engaged in it. In the Guardian yesterday, Laurie Penny reflected on the 4chan hoax, painting a picture of sad men angrily reacting against the growing and successful movement of internet feminists. Well, possibly, but it is just as likely that a lot of people enjoy the vicarious thrill of insulting others and running away. There is something pretty pompous about the rigid etiquette of the Twitter activists’ call-out culture that begs to be mocked.

If hashtag activism is easily parodied, then that shows what is wrong with it. By drawing out the excessiveness of hashtags like #SolidarityisforWhiteWomen or #KillAllMen, the 4channers were doing everyone a favour. The wisest point about Twitter was made by playwright Steven Berkoff: if you jump in a dustbin you cannot complain that you are covered in rubbish. In the meantime, we should be grateful to the guerrilla activism of Operation Lollipop. From now on, every strident statement on Twitter will rightly be questioned: is this a real sentiment, or does it sound more like a parody? As Laurie Penny tweeted when the story broke: ‘Sudden moment of existential dread, wondering if I am myself a 4chan creation.’