It has never been difficult to distinguish between David Cameron and a humble man plagued by self-doubt.

The former prime minister’s most prominent trait in power – and probably the reason he lost it – was his combination of blithe confidence with peevishness when challenged by people he judged to be his social inferiors, which covers most people. So it is not surprising to learn now, in a TV interview, that Cameron is satisfied with the decision he made to call an EU referendum (“I believe I was right”), while also believing the outcome was a bad one (“we’ve taken the wrong course”).

No one likes admitting error. For public figures it can be ruinous. That is why political apologies tend to adopt the passive voice – “mistakes were made”; “sorry for upset that was caused”; “sorry if offence was taken”. There is nothing new in this, but it feels as if political responsibility has become especially diffuse recently. There is a culture of treating bad things that happen as acts of nature, hurricanes that formed somewhere out at sea, beyond view, and blew in without discernible cause.

Theresa May, under duress, apologised for anxiety caused to the Windrush generation, whose entitlement to the security and privileges of British citizenship was callously shredded. But the prime minister is unable to articulate what, or who, caused the anxiety. Earlier this week she tried to deflect blame on to the last Labour government, as if no one would notice that her narration of the scandal omitted the operation of the Home Office between 2010 and 2016, when she was in charge of it.

May’s motivation here is old-fashioned tactical evasion and partisan counter-attack, albeit not very effectively executed. But she also conveys a sincere belief in her own immunity from blame. She is not conceited in the haughty Cameron mould. She certainly doesn’t carry herself with effortless social aplomb. But her shyness must not be mistaken for modesty. She has a different kind of arrogance: a pious certainty of moral purpose that allows her to imagine her critics must be driven by motives shabbier than hers. (This, notably, is a trait she shares with the leader of the opposition.)

Partly that is just a feature of a long-serving politician. A certain thickness of skin is required to survive Westminster’s vicious contact sport. And once you get into the habit of surviving criticism, it is easy to evolve the belief that none of it is justified.

But there is a more profound diffusion of responsibility in British politics right now. It flows from the perversity of a government committed to a course of action that the incumbent prime minister could not bring herself to recommend to the country in a referendum. A monumental, epoch-defining thing is happening. Yet no one who believed in the idea before it became a political reality has executive control over the outcome.

Theresa May at the executive session of the Commonwealth Heads of Government meeting. Photograph: Tolga Akmen/AFP/Getty Images

Boris Johnson, the highest-ranking leave campaigner in government, would rather hint that he is unhappy with the choices May is taking than demonstrate the courage required to unseat her and test different choices in practice. The foreign secretary embodies a common desire to enjoy the status of an office without the responsibility contained in that office. He wanted his ambition to be inflated by the spirit of Brexit, but not to own the consequences of Brexit.

Johnson was not in Cameron’s cabinet, but the model of being pro-leave in government, without having to explain how a government might safely go about leaving, was pioneered by the former prime minister. He was so confident of winning the referendum that he allowed Tory Brexiteers to campaign against him without surrendering the security of their ministerial berths. He suspended cabinet responsibility, allowing colleagues to serve the government in the morning, criticise government policy in the afternoon, and join rallies with the government’s sworn enemies in the evening.

Brexiteers have subsequently been accused of wanting to have their cake and eat it. But for years Cameron indulged radical Euroscepticism as if it were a manageable eccentricity or cultural foible, wholly compatible with the demands of responsible government. He ran the magic cake shop for Tory politicians.

He did this because he worried about splitting the party and imagined that was the likelier hazard than Britain actually leaving the European Union. When it turned out he was wrong, he shrugged and left the stage, humming a little tune, with the jaunty gait of a man who has never had to clear up his own mess; whose tables have always been laid before he arrives and cleared by the staff after he leaves.

And now, nearly two years later, he tells us he thinks he made the right choices. Former prime ministers aren’t generally in the business of trashing their own legacies and, since the Brexit plebiscite is certain to be Cameron’s biggest contribution to the history books, he doesn’t have much incentive to think of it as a monumental blunder. Also, his position is logically consistent. A democrat can be glad that the nation was consulted and accept, with a heavy heart, a disappointing verdict.

But Cameron’s heart doesn’t sound heavy. His manner is as breezy as ever. He seems to consider two notions – that the referendum was a good idea and that Brexit is a bad idea – as distinct entities in time and space and not part of a political sequence defined by actions for which he had responsibility.

He doesn’t have to be sorry that the referendum was held. But he might, as a courtesy to those who agree with his verdict on the result and who now live with the consequences, sound a bit sorry that he failed to win the argument; that he gambled with other people’s money and jobs, miscalculated the odds and blew it. He may not have wanted Brexit, but he still has to own it.

• Rafael Behr is a Guardian columnist