If you are a political archivist, there are two seriously covetable gigs in the world right now. The first is conceptualising the unprecedented annals facility that will one day be the Donald Trump Presidential Library. The second is collating the many different euphemisms for the Labour party having not won the recent general election.

At party conference in Brighton, you gotta catch ’em all. “We didn’t lose,” Emily Thornberry declared. “The real losers were the Tories.” At Momentum’s parallel event, the official literature noted that Labour had “witnessed possibility being snatched from the jaws of disaster”. In the conference hall proper, shadow business secretary Rebecca Long-Bailey elicited a huge cheer for “the biggest narrowing of the polls in British electoral history”.

Various other figures on the main stage offered a psephological version of the little homily Fred Savage used to voice over the credits of every episode of The Wonder Years, which typically began: “I learned a lot that day …” There was shadow leader of the house Cat Smith, who had learned: “We didn’t win the election – but we didn’t lose it either.” There was Unite union boss Len McCluskey, who declared: “I say we did win. We won the hearts and minds of millions of people, especially the young. We won the arguments that radical policies can stir the imagination and support of the British people. And, perhaps most of all, we won back our dignity and pride …”

Oh, Len! Did it turn out to be about the friends we met along the way? Pretty sure that all that glitters is not a majority, and that falling 60 seats short turned out to be the greatest treasure of all. Anyway, we will be hearing more from Len later, on the matter of the Jews.

Laugh? It’s the way he tells ’em: Len McCluskey at the Brighton conference. Photograph: Matt Crossick/Empics Entertainment

For now, just as the thing to say to the parents of the bride in a wedding receiving line is: “You must be very proud”, the thing to say at Labour conference is: “What a difference a year makes.” (Obviously, I also plan to say this every three minutes at Tory conference, and with a peal of laughter.)

Anyway, what a difference a year makes. Last year, I watched Jeremy Corbyn being shepherded round the official conference stands, with our perennial outsider stopping at one and reflexively posing for a photo holding up their placard reading “Bring Back the Shadow Cabinet Minister for Mental Health” – a post he himself had scrapped a few months previously. This year, he walked into the party conference like he was walking on to a yacht. “His hat strategically dipped below one eye, his scarf it was apricot. He had one eye on the mirror as he watched himself …” Well, you get the idea with that one.

And, in fairness, he thinks the song is about him because it is about him. You can even buy football scarves bearing a reminder of the lyrics: Oh, Jeremy Corbyn! (Although the scarves are red, not apricot.)

These days, everyone ambitious gave the impression they would much rather be at Momentum’s concurrent conference, called The World Transformed, which now lands multiple shadow cabinet ministers as speakers, alongside Corbyn, prominent younger activists and radical left thinkers. The World Transformed was spread across nine venues around town, and there was even a creche (for children, not journalists). It was staffed mainly by young people who had all bought the T-shirt (literally), and were very energetic and enthusiastic.

Aside from the various opportunities to work with the meditative medium of clay, most of the events were politically practical. There were lots of sessions explaining how the Labour party machinery worked, which is helpful, as without them it takes slightly longer to grasp than it does to master neonatal laparoscopy. There were plenty on organising, and winning arguments, though I did hear one audience member call for Labour MPs to be politically “re-educated” – alarm-bell word – on account of their being “anti-theoretical and politically illiterate”. Without wishing to lean too heavily on arcane neo-Marxist terminology here, that just sounds like a load of wanky rubbish. At best.

Welcome to the play pen: visitors at clay workshop at Momentum’s The World Transformed programme. Photograph: Matt Crossick/Empics Entertainment

Then there were things such as How to Win a Marginal with Chris Williamson, who I always think of as Labour’s Shirley MacLaine, on account of his devotion to various fringe lunacies. Is this the same Chris Williamson who kept “MP” in his Twitter handle for two years after losing his seat? That’s an easy way to win a marginal.

Occasionally, the Momentum programme was designed as deliberately provocative, as with Acid Corbynism, an event Clive Lewis informed me “will make your front teeth drop out”. That’s Crystal Meth Corbynism, Clive. Acid Corbynism surely has alternative effects, unless it is going to cause a mass exodus of dentists (possible). Slightly disappointingly, there were no books of poetry about Corbyn on sale at The World Transformed, as there were last year. According to one of the organisers: “We’ve professionalised.” Sellouts! That’s how it starts: one minute you’re phasing out verse about Jeremy Corbyn lighting a candle in all our hearts; before you know it, you’re getting involved in a land war in Asia.

Speaking of which, conference also featured a cautionary visit from the Ghost of Christmas Future. In one of the screens at Brighton’s Odeon cinema, Progress held a rally for Labour moderates. Outside the room was a 6ft-high poster for Flatliners. Harsh. Still, hard to disagree. Labour centrists have clearly decided resistance is futile (or, at least, professionally undesirable). Watching people – including Sadiq Khan and Tom Watson – give rapturous speeches on the main stage this week, in which they directly contradicted their earlier “principled” objections to Corbyn, serves as a reminder that we overuse the word principle. It’s not really a principle if it gets buried when the thing it was objecting to does better than expected.

Frequently, this conference served as a reminder that when you’re hot, you’re hot – but when you’re not, you’re really not. “Ten years ago,” Ben Bradshaw told the Progress rally, “I had the experience of walking in here as a minister in our great government, with all the protesters and people giving you leaflets outside. This year, I was one of those protesters.” That, as David St Hubbins once observed, is “too much fucking perspective”. Still, the trading of places is not without comic effect, and it is occasionally difficult not to giggle at the spectacle of formerly overpromoted masters of the universe on the other side of the velvet rope these days.

Momentum gets a lot of stick for a certain strain of its needling – branding people “centrist dads” and so on. But it rather reminds me of that episode of The Simpsons where Bart inquires of a man: “I’m Bart Simpson – who the hell are you?” “I’m Dave Shutton,” comes the stuffy reply, “an investigative reporter who’s on the road a lot, and I must say that in our day we didn’t talk like that to our elders.” “Well, this is my day,” shrugs Bart, “and we do.” And so with many of Momentum’s in-jokes – there is something Bartishly irreverent and invigorating about them, and pants ought not to be wet in response. All the grownuppery was far more off-putting, anyway. Emily Thornberry kept insisting Labour were “the grownups”, while Keir Starmer echoed that the party was “the grownups in the room”.

Come on you reds! The proud owner of a Jeremy Corbyn scarf. Photograph: Anadolu Agency/Getty Images

Even so, it was hard not to get a bit lost on who the bad guys are. I saw erstwhile McDonald’s ad director Ken Loach on Sky News sticking it to Clement Attlee’s government for “propping up a capitalist economy” – a mistake Corbyn won’t be making, apparently. Ken’s other noteworthy contribution was to join Other Ken (Livingstone) in another deeply called-for denialist riff on Labour’s antisemitism problem.

The Kens’ comments will further depress the Jewish delegates and members of the party I talked to, who were miserable about the issue and felt – how to put this mildly? – that the policy of not dealing properly with the problem had not been the success one might have hoped. Yet the openly professed concerns of Jewish delegates were rubbished as “mood music” by McCluskey. Let’s see that in action: “I believe it was mood music,” McCluskey told Newsnight, “that was created by people who were trying to undermine Jeremy Corbyn.” Lovely. Whenever people combine easy charm with adorable dismissiveness in this manner, I am reminded of the story about Princess Margaret attending a screening of Schindler’s List. As she exited, she was allegedly overheard remarking to her walker: “Oh, those fucking Jews, always moaning.”

Then again, absolutely everything unfortunate these days is widely regarded as a conspiracy against Jeremy. One delegate told conference that Sunday’s Brexit protest in Brighton was “an absolute disgrace” because it “undermines the leadership of Jeremy”. For his part, Austin Mitchell, a former Labour MP and leave supporter, mocked those protesting against Brexit, deciding they were “public schoolboys on community service”. I think that’s the leader’s office, but go on. The protesters were “flag-waving fools”, he judged.

For all the muscular positivity on show, it was hard not to experience this as a conference of contradictions. Visitors to The World Transformed could admire a large hand-embroidered blanket on the wall, reading: “If foe, our love shall conquer thee.” Maybe it could serve as a protective cloak for Laura Kuenssberg, for whom the BBC felt required to hire a bodyguard for this conference. Asked to comment on the depressing spectacle of the BBC’s first female political editor requiring protection at a Labour conference, John McDonnell said that if anyone heard any abuse, they should tell him, because “John McDonnell will sort ’em”. Attaboy. Be the change you want to see.

Then there was Momentum founder Jon Lansman declaring: “We need to get away from the Blairite authoritarian model where dissent was not tolerated,” even as he helped mastermind a classic old-style fix that ensured no Brexit vote took place. Still, as one delegate deathlessly informed conference, it was good the vote hadn’t happened, because “we would have disagreed”. Elsewhere, there was a Free Speech on Israel event where the audience were banned from taking photos, filming, recording or tweeting.

Meanwhile, despite the fact it would be a task beyond Bletchley Park to decode Labour’s Brexit policy, Keir Starmer accused the Tories of Brexit incoherence. A lot of people query this kind of stuff, but I prefer to let the contradictions wash over me like a really inoffensive spa music CD.

Delegates keep the Red Flag flying. Photograph: Gareth Fuller/PA

Less easy to surrender to was the wall-to-wall, worshipful defensiveness. After three days of carefully controlled organisation, the endless reminders to “respect Jeremy” could get slightly wearing. I was starting to respect this respect campaign about as much as I did New Labour’s “respect agenda”. “Jeremy told me: no jokes,” said McDonnell after some humblebrag relating to the so-called McDonnell amendment, “but I couldn’t resist that one.” Everywhere else, non-official, non-approved humour felt like something very much to be resisted. My own experience is that many of the same people who just love it if you are cheeky about the Tories get incredibly hot under the collar if you are cheeky about Corbyn.

The disloyalty simply can’t be borne, and – however counterintuitive it may sound – this tendency should be seen as a far more worrying concern than most of the policy directions. I increasingly fear that the spirit of the age was best caught by Ian Hislop a couple of years ago, when the Private Eye editor explained: “There are a lot of people who’ve discovered politics recently but haven’t got the idea that – in the world of politics – it’s possible for the opposition a) to have a point and b) to offer criticism. So a lot of Ukippers cancelled their subscriptions earlier in the year because they thought the jokes about Ukip were not funny and not fair. This was followed by a very similar vein of Scots Nats saying: ‘These jokes aren’t funny, and they’re not fair.’ And I think we’re about to get the Corbynistas, that’ll be the next wave saying: ‘You’ve no idea what you’re talking about.’ A different sort of politics has just arrived – whether it’s Farage or Sturgeon or Corbyn. And any criticism – and certainly any jokes – are not welcome.”

The hall reacts to Corbyn’s final-day speech. Photograph: Anadolu Agency/Getty Images

A year or so after this, Hislop delivered the Orwell lecture he entitled The Age of Outrage, by which point he was able to confirm that the Corbynite cancellations had indeed come. They, in turn, had been followed by the Brexiters, with a single cover involving the £350m red bus drawing a tide of frothing condemnation and terminated direct debits.

I spoke to Hislop this week, and he mentioned seeing the play Oslo, which is about the secret talks that led to the 1993 Oslo accords between the Israeli government and the Palestine Liberation Organisation, and in which jokes – often off-colour ones – are regularly shown to break the impasse, to kickstart something that has stalled, or to dissolve tension and resurrect the possibility of common ground.

We need jokes now – if not more than ever, then certainly as much as ever. Everyone who dishes them out – from journalists to idealistic activists to shadow ministers – should be able to take them, and not seek refuge in the ominous language of sacrilege and blasphemy. Yet in a divided era when we must most urgently find common ground to face many complex and unprecedented challenges, a new and toxic puritanism has descended on both the radical left and the radical right. The entire purpose of jokes and criticism has been misunderstood (either wilfully or ignorantly) – and on the evidence of much of this week in Brighton, the people doing the misunderstanding are powerfully in the ascendant.

• This article was amended on 29 September 2017. The original referred to the PLO as the Palestinian Liberation Organisation. This has been corrected. An earlier version referred to Austin Mitchell as a Labour leave MP. Mitchell stepped down in 2015.

