Earlier this year, Michael Bates, an obscure minister in the House of Lords, offered his resignation because he was “ashamed” at having not been in his place in the chamber in time to answer questions. The prime minister advised the Queen not to accept it.

Quitting for being late for work was regarded as laughably eccentric by colleagues whose shame threshold is set so high it can’t be seen. As I write, Amber Rudd and home secretary can still be put in the same sentence without it including the word former. Her non-resignation from the cabinet, despite a mammoth scandal perpetrated by the major department for which she is responsible, tells us something about this government, something about its opponents and more about shifting standards in public life. None of the things it tells us is good.

The suffering inflicted on “the Windrush generation” has been abominable. I struggle to recall an example in modern times of a British government treating such a large group of its citizens so atrociously. It takes a particularly noxious combination of incompetence and inhumanity to tell people who have been living in Britain entirely legally and for many decades that they are going to be thrown out. To which was added the cocktail of myopia, soullessness and arrogance that meant ministers only started to respond to this scandal when it got the national attention it deserved five months after Amelia Gentleman broke the story in the Guardian.

Q&A What is the Windrush deportation crisis? Show Who are the Windrush generation? They are people who arrived in the UK after the second world war from Caribbean countries at the invitation of the British government. The first group arrived on the ship MV Empire Windrush in June 1948. What happened to them? An estimated 50,000 people faced the risk of deportation if they had never formalised their residency status and did not have the required documentation to prove it. Why now? It stems from a policy, set out by Theresa May when she was home secretary, to make the UK 'a really hostile environment for illegal immigrants'. It requires employers, NHS staff, private landlords and other bodies to demand evidence of people’s citizenship or immigration status. Why do they not have the correct paperwork and status? Some children, often travelling on their parents’ passports, were never formally naturalised and many moved to the UK before the countries in which they were born became independent, so they assumed they were British. In some cases, they did not apply for passports. The Home Office did not keep a record of people entering the country and granted leave to remain, which was conferred on anyone living continuously in the country since before 1 January 1973. What did the government try and do to resolve the problem? A Home Office team was set up to ensure Commonwealth-born long-term UK residents would no longer find themselves classified as being in the UK illegally. But a month after one minister promised the cases would be resolved within two weeks, many remained destitute. In November 2018 home secretary Sajid Javid revealed that at least 11 Britons who had been wrongly deported had died. In April 2019 the government agreed to pay up to £200m in compensation. Photograph: Douglas Miller/Hulton Archive

As a result of the government’s casual cruelty, victims have been evicted from their homes and lost livelihoods. They have been denied urgent medical treatment, forcibly separated from loved ones and been deprived of their liberty in detention centres. Many have been subject to intolerable stress.

“Appalling” is one of Ms Rudd’s descriptions, part of a strategy of trying to think of the most damning label that could be affixed to her department and then saying it before someone else does. She has proferred grovelling apologies. So has the prime minister, but only belatedly and under duress. It took the electric cattle prod of universally hostile headlines before Mrs May uttered some sorries to the victims and the leaders of Caribbean states who were here for the Commonwealth Summit.

Sorry is not the hardest word in politics. Apologise is the first line of advice in the PR disaster management manual. Apologies don’t cut it as proper redress for the victims. I expect they will receive compensation, although not out of the pockets of the authors of this scandal, but from the earnings of the general taxpayer.

What we haven’t seen is the only penance that really means anything with politicians. There have been no resignations. Lives have been wrecked; Westminster careers sail on. Ms Rudd’s reputation has taken a battering, but she is still in her ministerial suite, still cruising around in her government limo and still drawing her cabinet salary. This is partly down to the place she occupies in the febrile kaleidoscope of Tory factions. She is generally agreed, among friends and foes, to be on the more liberal wing of her party. It has to be said that she sometimes has a highly peculiar way of expressing her liberalism. For her first party conference speech in post, she produced a widely denounced and swiftly dropped plan to compel companies to list their foreign workers.

Though her public pronouncements have hinted at divisions between herself and the prime minister on immigration policy, a recently leaked memo reveals Ms Rudd to be anxious to impress the boss at Number 10 by boasting that she was giving more “teeth” to the deportation programme inherited from Mrs May. Ms Rudd’s standing among more liberal Tories, who see her as a potential standard bearer in a future leadership contest, nevertheless persists. Liberal Tories have not wanted to go after a minister they regard as one of their own and even less so when the Brexiters have been gunning for one of the cabinet’s prominent Remainers.

Jeremy Corbyn was banjaxed by Theresa May at Prime Minister’s Questions. Photograph: PA

More surprisingly, perhaps, the Labour frontbench has not roared for the head of Ms Rudd with the ferocity you get when the opposition is really determined to scalp a minister. This is mainly because Labour has sought to look through the home secretary in order to go after the prime minister. As a matter of political justice, this is entirely fair. This scandal flows from the legislation and culture introduced during Mrs May’s domineering five years in charge of the Home Office. She brought in a slew of measures designed to create what she called a “hostile environment” for illegal immigrants by turning landlords, employers and NHS staff into a pressed gang of border guards. It was the application of that policy that ended up snaring people who should never have been targeted. That has fuelled a desire on the part of campaign groups and opposition politicians to widen this episode from the appalling treatment of the Windrush generation to a more general argument that policy towards migrants is nasty and discriminatory. Broadening the charges against the government is understandable, but may have had the unintended effect of helping it to endure the specific scandal.

Labour’s attack was blunted when it got entangled in the weeds of who was responsible for the destruction of the victims’ landing papers. This was the point on which Theresa May banjaxed Jeremy Corbyn at prime minister’s questions. The opposition has also struggled to bring maximum pressure to bear on the government because of Labour’s own divisions. The day before Mr Corbyn’s flop at the dispatch box, he had to sit through a debate in which some of his own MPs detailed the anti-semitic abuse they have received from people declaring themselves to be supporters of the Labour leader. Mrs May could do a I-won’t-take-any-lectures-from-him routine when Mr Corbyn called her “callous”.

The absence of resignations over the Windrush scandal illuminates something deeper: a more general change in the political culture that has made it tougher to hold ministers accountable for their failures. It is not true to say that “no one resigns any more”. There has been a high casualty rate of cabinet ministers since the Conservatives came to power in 2010. Mrs May has lost three cabinet ministers in just six months. Damian Green was forced out as deputy prime minister at the turn of the year. Michael Fallon was made to resign last autumn over his conduct towards women and Priti Patel went for unrelated reasons around the same time. In the Cameron years, David Laws, a Lib Dem, and Maria Miller, a Tory, went over allegations about expenses. Chris Huhne had to go, and was later jailed, because of his lies over a speeding ticket. Andrew Mitchell was made to quit – rather unfairly – over what was known as “plebgate”. Liam Fox, who has since come back, resigned when he was being investigated amid allegations that he had breached the ministerial code.

These resignations can be broadly grouped under the heading “personal conduct”. What no one ever quits over is maladministration and policy blunders, however atrocious. There are just as many of these as there ever were – as I say, it is hard to think of a case more reprehensible than the Windrush scandal. That has had much more serious consequences for citizens than deficiencies in personal conduct for which ministers have lost their jobs. Yet no one carries the can.

There used to be a convention that a minister took responsibility for his or her department’s disasters – and did so even if the blame lay with officials rather than the secretary of state. That convention now seems to be entirely dead. Ministers who preach responsibility and accountability to the nation never shoulder it themselves.

The home secretary can also thank her survival to another debasement in the culture. A lot of political discourse has become shriekingly hyper-partisan. That, in a perverse way, has actually rendered it harder to hold ministers to account. Mrs May and her cabinet are daily lambasted by their opponents and the same hyperbolic language tends to be employed over any issue, whether it be significant, second rank or trivial. Words such as “shameful” and “disgrace” and “despicable” are hurled around in parliament, in broadcasting studios and even more so on social media. They are thrown about in such a routine, ritualised way that the words are losing their power to sting ministers on the occasions when excoriating language is entirely deserved. The trouble with using the vocabulary of outrage to describe everything about this government is that it makes it harder to nail ministers when there is an authentic scandal. It is making it easier for Ms Rudd and Mrs May to weather this one.

• Andrew Rawnsley is an Observer columnist