The steady creep of “sex work” into 21st-century vernacular is neither incidental nor accidental. The term didn’t just pop up and go viral. The Global Network of Sex Work Projects (NSWP), an organisation that openly campaigns for brothel-keeping and pimping to be recognised as legitimate jobs, credits itself as largely responsible for “sex work” replacing “prostitution” as the go-to terminology for institutions such as the Joint United Nations Programme on HIV/Aids (UNAIDS) and the World Health Organization (WHO).

“More than mere political correctness,” the NSWP proudly states, “this shift in language had the important effect of moving global understandings of sex work toward a labour framework.” The fact that prostitution involves sexual acts and some kind of payment is a given. However, engaging with it first and foremost as a labour issue, using the term “sex work” as if it was an adequate and appropriate shorthand for what takes place in strip clubs, on porn sets and in brothels, serves a deeply political goal. Not only does this framework shrink the field of analysis to the seller (to the exclusion of men’s demand and its social impact), it hides what should be front and centre of our response to the transaction: the inherent sexual abuse.

The notion that being paid to perform sex acts should be recognised as a kind of service work is the rationale underpinning legalised prostitution regimes. It’s an idea that has managed to unite an eclectic mix of left and rightwing voices. Peter Frase – a member of the editorial board of Jacobin, a magazine billed as a leading voice of the American left – is in favour of “legalising all forms of sex work for adults”. He claims: “Not only does sex work destabilise the work ideology, it also conflicts with a bourgeois ideal of private, monogamous sexuality.” Tim Worstall, writing for British rightwing thinktank the Adam Smith Institute, shares Frase’s policy conclusion, though his reasoning contrasts somewhat. As a type of commercial activity, Worstall insists the prostitution trade is “obviously free market” and that “renting out body parts is and should be no different from lending them out for fun or for free”.

The whole point of the sex industry is that it offers men the chance to buy sexual access to women who do not want to have sex with them – otherwise they wouldn’t have to pay. Masking its fundamental purpose thus becomes the primary PR challenge for the prostitution, pornography and strip club trades if they are to survive – maybe even thrive – in a society that has decided, at least in principle, that women are not subordinate sex objects and rape is a bad thing.

Perhaps the single most effective strategy hit upon so far is to pump out the myth contained in the term “sex work”: the myth that it is possible to commodify consent.

How can sexual consent be a thing that can be bought and sold, yet we can still talk with a straight face about there being such concepts as healthy sexual relationships and meaningful consent? If, while having sex with someone, you feel repulsed by them touching you, afraid of what they might do, degraded and humiliated by the sexual acts, hurt by the hateful words they’re whispering in your ear, sore because he’s the fifth man you’ve had sex with today, exhausted from it all, traumatised, abused – the fact that you’ll get a bit of cash at the end does not change anything. There is no invisible hand in the prostitution market that magically disappears the lived experience of sexual abuse.

‘The term “sex work” is a myth: the myth that it is possible to commodify consent.’ Photograph: Justin Tallis/AFP/Getty Images

Poverty can, of course, play a highly influential role in women’s entry into prostitution. However, bluntly asserting that poverty is the singular cause of the prostitution trade fails to acknowledge that men’s poverty has not begot a global demand from women to pay them for sex acts, that without men’s demand there would be no trade at all, or the highly specific abuses that so commonly characterise women’s entry into it.

Research by the British Medical Journal found that, in three UK cities, half of women in outdoor prostitution, and a quarter of women in indoor prostitution, reported having been subject to violence by a sex buyer in the previous six months. Of the violence they had ever experienced at the hands of sex buyers, women on the streets most frequently reported being kicked, slapped or punched, while women in saunas or flats most frequently reported attempted rape (17% of women based indoors had experienced this, as had 28% of women on the streets). A separate study, in Sociology of Health and Illness, involving more than 100 women engaged in flat-based prostitution in London, highlighted how an indoor setting can have its own particular coercive influence. Each day women had to pay up to £250 in rent, as well as up to £60 a day for a maid (who, in practice, often operated like a pimp, sometimes controlling which sex buyers the women saw), plus a range of other expenses. On average, a woman was paid for sex by 76 men each week.

The Economist’s 2014 article, titled A personal choice, warding off “puritans and do-gooders” from meddling with the sex trade, insists that governments should “leave consenting adults who wish to buy and sell sex to do so safely and privately online”. This builds on the claim that prostitution is sex work by attempting to frame that work simply as a series of individual, private exchanges set apart from the rest of society. Milton Friedman, the late economist and proponent of unbridled free-market capitalism, implied much the same when asked about prostitution in 2006. “You put a willing buyer [with] a willing seller, and it’s up to them. You can argue with them that it’s foolish, you can argue with them that it’s a bad thing to do, but I don’t see any justification for bringing the police into it.” But the sex industry, like any market, doesn’t operate in a vacuum, leaving the rest of society miraculously untouched by its presence. Markets are, as philosopher Debra Satz says, social institutions: “All markets depend for their operation on background property rules and a complex of social, cultural, and legal institutions.” Markets are a matter for everyone.

Neon sign advertising a live model or prostitute. Photograph: Photofusion/UIG via Getty Images

Trades weave themselves into the fabric of society. We know this. We place all kinds of restrictions and prohibitions on markets precisely because of this. Because the risks, particularly to the most vulnerable and marginalised in society, are just too high. Commercial exchanges that people may agree to participate in without a gun being held to their head – such as sales of human organs, voting rights, bonded labour contracts – are nonetheless deemed legally off limits. It’s the line in the sand that societies draw to say that the harm to those directly involved, to third parties, or to the bedrock principles necessary for equal citizenship, is simply too great. Some trades are too toxic to tolerate.

A basic principle that is utterly indispensable to ending violence against women, not to mention to our fundamental concept of humanity, is that sexual abuse is never acceptable. Not even when the perpetrator has some spare cash and the person he’s abusing needs money. Cheerleaders of brothels, porn sets and strip clubs would have us believe that the sex trade levitates above the level of social values and cultural beliefs. But no one can opt out of its effects. A market in sexual exploitation, accepted and tolerated, influences who we all are as individuals, and who we are as a people.

A society that acts in law and language as if men who pay to sexually access women are simply consumers, legitimately availing workers of their services, is a society in deep denial about sexual abuse – and the inequality underpinning it.

•Pimp State: Sex, Money and the Future of Equality by Kat Banyard (Faber & Faber, £12.99). To order a copy for £10.39, go to bookshop.theguardian.com or call the Guardian Bookshop on 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min. p&p of £1.99.