Ten days or so ago, on the great sunlit upland of empathy and rational debate that is Twitter, the science writer Ben Goldacre drew his followers’ attention to an image posted by someone else. “Brexit voters get tremendously upset when you say they are racists and idiots,” he said. Below was a Venn diagram, with one ring each for “racists” and “idiots”, and an intersection labelled “racist idiots” – which, said Goldacre, “communicates the issue very clearly”.

Last Wednesday the New York Times ran a column by the journalist Roger Cohen headlined The Madness of American Crowds, partly about the Americans who voted for Donald Trump – who, he baldly claimed, were simply “mad”. “People are weak,” he wrote. “They are susceptible. They are easily manipulated through their fears. They long to prostrate themselves. They can be led by the nose into the gutter. The angels of their better natures, if they’ve ever given a moment’s thought to them, are a lot less powerful than the devils of their diabolical urges. They lie, they exploit, they seek distraction at any price from the monotony of existence.”

Just about all of us cast our votes at least partly on the basis of gut instinct and beliefs only partly rooted in truth

Back in 2016, it was briefly fashionable to feign interest in at least some of the places that voted for Brexit and Trump and argue that people with so-called progressive politics ought to think about their problems. But in some quarters, the “in” thing is now a sour, dismissive attitude to millions of people and their supposed complaints. The underlying worldview is simple: whatever the economic context, one part of society is seen as racist, stupid, nostalgic, and brimming with senseless emotion, while another is logical, enlightened and forward-thinking and, despite the fact that the era of alleged rationalism that has now been overturned brought us such disasters as the Iraq war and a huge economic crash, the modern nightmare boils down to the fact that the first group are suddenly in charge.

For some people at least, Brexit is now a pretext for simply standing back and smugly scoffing at the fate of the places where a majority of people voted for it. In a recent issue of the anti-Brexit newspaper the New European, one columnist articulated the basic argument: “The north-east and the Midlands voted for Brexit. Yes, I know they almost certainly did so unwittingly against their own economic interests, but democracy isn’t, ‘Get what you vote for, unless you’re wrong and then we’ll fudge it for you from there.’ I’m sorry that those areas will suffer, but such is the price of democracy.”

If this kind of thinking is your cup of tea, it now has intellectual underpinning. The Harvard psychology professor Steven Pinker has just published Enlightenment Now, a doorstep-sized statement of the case for “reason, science, humanism and progress” against what he calls “progressophobia”. Among other things, Pinker believes that across the west and beyond, people are actually “getting healthier, richer, safer, and freer”, and that inequality “is not in itself a dimension of human wellbeing, and … should not be confused with unfairness or with poverty”.

He tends to represent the world either in graphs, or the kind of bromides that suggest someone glancing at the world from a speeding Prius, en route to a TED talk. “The old stereotype of poverty was an emaciated pauper in rags,” he writes. “Today, the poor are likely to be as overweight as their employers, and dressed in the same fleece, sneakers and jeans.” He rejoices that people on low incomes have such basics as electricity, running water and colour TVs – “a century and a half before, the Rothschilds, Astors and Vanderbilts had none of these things”. The punchline: “The rich have gotten richer, but their lives haven’t gotten that much better.”

It might all suggest nothing more harmful than a supposedly clever person managing to sound stupid – were it not for the way that it so snugly fits its time. By implication, the allegedly disadvantaged people who voted for Brexit and Trump are actually not that disadvantaged at all, and Pinker suggests the reasons they rallied to populism can be placed squarely in the realm of emotional prejudice and resistance to “progress”.

Pinker’s book evokes the same liberal misanthropy now swirling around Brexit. “Most voters are ignorant not just of current policy options, but basic facts,” he says. And woe betide anyone who publicly questions the idea that progress is continuing apace, and no fundamental rethinks are required. “I believe that the media and intelligentsia were complicit in populists’ depiction of modern western nations as so unjust and dysfunctional that nothing short of a radical lurch could improve them,” he says, seemingly ignoring the fact that 10 years after the crash there is still rather a lot of injustice and dysfunction around.

Do we have to go through all this again? Referendums are almost always silly and dangerous things, but we had one, and nearly three-quarters of the electorate took part in it. Just about all of us – remainers included – cast our votes at least partly on the basis of gut instinct, tribal affinities, and beliefs only partly rooted in undeniable truth.

As with the coalition that elected Trump, a lot of the people who still staunchly support leaving the EU are comfortably off. Some are undoubtedly fired by bigotry. But many defy such easy stereotypes. A lot of them live in places to which politicians have not paid any meaningful attention in decades, where people have suffered nearly eight years of austerity – and, thanks to the deindustrialisation callously let loose in the 1980s, issues around immigration have become tangled up in a dire lack of homes, dependable jobs and basic opportunities. It may fly in the face of the boundless optimism proffered by Pinker, but in a lot of these places, in terms of basic security and a collective belief in the future, life was probably better 40 or 50 years ago.

In Britain and elsewhere, the liberal left has still not found the language to speak to that sense of loss. Even now, a lot of the people who feel it see Brexit as the better of two options: the continuation of the way things were before, or a chance to at least upturn the tables, bring decision-making much closer to home and somehow start again. This is not to dispute that Brexit is a bad idea, or that the people who have taken charge of the process are inept beyond words. But if you reduce the reasons why so many people voted for it to mass prejudice and stupidity, you are guilty of the same transgression the liberal misanthropes wail about: the denial of fact.

Perhaps the most important point applies to the kind of blighted, post-industrial areas that are as relevant to the defeat of the UK’s pro-Europeans as they are to the Democrats’ loss of the presidency. It takes real strength to make a life in those places. Most people there do not long to prostrate themselves but to walk tall. The angels of their better natures are present and correct, if only the supposed forces of progress would finally create conditions in which they could fly. Have we forgotten so quickly?

• John Harris is a Guardian columnist