A Swiss mountain retreat for global business elites is not the obvious place to meet sworn enemies of capitalism. It is more the kind of place to hang out with aspiring European finance ministers. That John McDonnell happens to be both of those things makes him one of the more exotic guests at the World Economic Forum in Davos this week.

McDonnell’s attendance is less surprising than it would have been a few years ago. When the shadow chancellor and his friend Jeremy Corbyn were rebellious Labour backbenchers, they had no time for oligarchic Alpine jamborees. (Plus they weren’t invited.) That old scorn might not have been forgotten, but the prospect of real power – not anticipated by either man before last year’s election – imposes new nuances of tone. According to a spokesman, McDonnell travels to Switzerland “to explain Labour’s vision for an alternative economic approach to replace the current model of capitalism”.

From a man who once itched for socialist revolution, that sounds like tempered zeal. Those in Labour’s top team leave audiences in no doubt of their dislike of markets and the private sector, but the closer they get to high office, the more coy they are on the question of how much of either should be allowed. Is capitalism to be mended or ended?

Quick guide What is Davos 2020? Show Hide Davos is a Swiss ski resort now more famous for hosting the annual four-day conference for the World Economic Forum. For participants it is a festival of networking. Getting an invitation is a sign you have made it – and the elaborate system of badges reveals your place in the Davos hierarchy. The meeting is sponsored by a huge number of international banks and corporations.

For critics, “Davos man” is shorthand for the globe-trotting elite, disconnected from their home countries after spending too much time in the club-class lounge. Others just wonder if it is all a big waste of time. The 2020 meeting is being advertised as focusing on seven themes: Fairer economies, better business, healthy futures, future of work, tech for good, beyond geopolitics and how to save the planet. Young climate activists and school strikers from around the world will be present at the event to put pressure on world leaders over that last theme.

To the terror of Conservatives, Corbyn is good at sounding moderate on this point. Attacks on the Labour leader as a terrorist-sympathising Bolshevik have not destroyed the target. A common interpretation of that failure in Tory circles is that younger generations are complacent about the benefits of the market, therefore easily seduced by the sirens of anti-capitalism. In this view, harrowing reminders of atrocities committed by Stalin and Mao might jolt naive Corbynites out of their ruinous utopian reverie.

Millennials do lack both memories of communist dictatorship and affection for Theresa May’s government. That doesn’t mean the former condition causes the latter. And there are plenty of older Labour supporters who remember the cold war without voting on that basis. A more useful way to look at the British left’s relationship with capitalism is as a kind of generalised cultural scepticism. Call it “capiscepticism”. This is the strong sense that the status quo is unjust, without adherence to any specific doctrine for replacement.

The capisceptic view of capitalism is analogous to the pre-Brexit Eurosceptic attitude to the EU – convinced it is bad but unfocused on the consequences of abandoning it. The distinction between loose cultural distaste and readiness for ideological destruction only became clear when a ballot forced the choice.

To develop the analogy further, capiscepticism’s relationship to hardline Marxism is rather like the relationship between Euroscepticism and Ukip-style xenophobic nationalism. There is overlap. But there are also adherents of the former view who despise the latter. They are offended when critics lump them together. Just as remainers did their cause no favours by depicting every leaver as a Farage-fancying maniac, today’s defenders of free markets are wrong to treat capisceptic voters as hollow-eyed, Lenin-loving cultists.

It is true there are enough hammers and sickles on display at Corbyn rallies to make a liberal heart sink. But the banners are mostly in the hands of older sectarian stalwarts. Doubtless their inclusion will harm Labour over time, just as May was unwise to splice chunks of Ukip’s political DNA into the Tory genome. But well-thumbed editions of the Little Red Book don’t begin to describe the wider sensibility that Corbyn has tapped into.

The modern capisceptic combines a lifestyle immersed in capitalism with a view of Britain’s economy as an engine of unfairness. I have met them in unexpected places: advertising, banking, the civil service. Many struggle to imagine Corbyn as prime minister, while thinking he has a point. They feel the insanity of a dysfunctional housing market. They resent bonuses for bosses who fail. They see different rules for the rich. That doesn’t make them Soviet revivalists.

Capisceptics might also be queasy about the control that vast corporations have acquired over every aspect of our lives, while struggling to imagine life without those companies’ services.

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This outlook can be satirised as the incoherent babble of a spoilt generation – the cortado-quaffing, iPhone-toting social justice warrior who shares memes about Facebook tyranny via Facebook. Highlighting the hypocrisies of capitalism’s critics as they enjoy its material bounty is sport for smug conservatives. More thoughtful Tories grapple with the new mood in earnest, but their efforts are hobbled by disbelief that the case for capitalism needs making at all. May had a dig at unscrupulous bosses over the weekend but in terms so laden with apologia for private enterprise, it was hard to discern the point she was making.

The vagueness of capisceptic politics also needs interrogating before it becomes an ethos of government. A lesson from Brexit is that it is easier to pile up grievances against a system than to map out alternatives. Once the despised object was rejected by ballot box, the impulse to reject turned out to be the only thing the sceptics had in common. Satisfying them all with a replacement is proving impossible.

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And, as pro-Europeans discovered, scepticism is a slippery opponent. It feeds on unfocused discontent and mistrust of authority without demanding commitment to specific policies. When it takes root in a culture it is not easily refuted by politicians telling the sceptics that things aren’t as bad as they look, or that opposition remedies would be worse.

Corbyn’s back catalogue overflows with criticism of capitalism, but he hasn’t pledged to do away with it. Whether that is the ultimate goal, kept under wraps for fear of alarming voters, is a question he ducks. When he is accused of alignment with extremes, his supporters don’t recognise the charge in themselves and they don’t see evidence for it in the leader’s recent speeches. They hear denunciation of austerity, neoliberalism, excessive privatisation and corporate greed, all of which can be understood as symptoms of a system in need of repair, or as synonyms for a system that must be completely destroyed. The scale of Corbyn’s radicalism – whether he intends reform or revolution, a tilt to continental social democracy or something more extreme – changes in the eye of the beholder.

There is no majority in Britain for full-blown anti-capitalism, but it does feel as if we are living through a wider capisceptic moment. In opposition the difference can be blurred. But not in government. It would be useful before the next election to know where Labour really stands.

• Rafael Behr is a Guardian columnist