It is a very Northern Ireland paradox: one of the most outspoken critics of the rioters who have been hurling petrol bombs at police Land Rovers is the hip-hop trio that rose to global fame literally atop a smoking police Land Rover.

Kneecap stormed the Sundance film festival this year when its members rode into Utah waving smoke canisters from the roof of a vehicle mocked up as a Police Service of Northern Ireland vehicle.

They also commissioned a mural of a burning police vehicle and similar imagery appears in the film about the group that has been named Ireland’s Oscar international feature submission and opens in British cinemas this week.

Naoise Ó Cairealláin, 30, aka the rapper Móglaí Bap, said it reflected distrust of law enforcement. “When you have rocket-proof jeeps on the streets and policemen with semi-automatic rifles it doesn’t really conjure up that feeling of community policing and love. It creates a real divide between the community and police.”

However in an interview with the Observer, Ó Cairealláin and bandmate JJ Ó Dochartaigh, 34, aka DJ Próvaí, reiterated the band’s criticism of the rioters in Belfast who attacked immigrant-owned property and rained missiles on police.

“They’re turning their anger at the wrong people,” said Ó Dochartaigh. A state that starved communities of funding should be the target, he said. “They should be aiming up … and not at these immigrants. It’s not long ago that the Irish were treated the exact same way whenever we went to England and other places around the world. People have a short memory.”

A burning police Land Rover, in other words, is all about context. It is a nuance, or contradiction, at the heart of one of the most controversial bands to emerge from the UK and Ireland since the Sex Pistols.

The trio – the third member is Liam Óg Ó Hannaidh, 26, aka Mo Chara – have fused the Irish language, republican totems, Troubles iconography and punk brio into a combustible mix that incites rapture and condemnation.

On stage and on screen they have blurred irony and provocation into high-octane performance that has wowed Glastonbury, won Sundance’s audience award and galvanised what some call an Irish language renaissance.

In the quasi-autobiographical film Kneecap, written and directed by Rich Peppiatt, the trio play versions of themselves with an ensemble cast that includes Michael Fassbender. The biopic is playing across the US, where distributor Sony is eyeing award nominations, and earned the biggest Irish box office weekend opening for an Irish language film.

The New York Times called the film gleefully chaotic. “It cruises on the strength of its underdog narrative and its weird, sordid touches.” Variety hailed a “riotous, drug-laced triumph in the name of freedom that bridges political substance and crowd-pleasing entertainment”. Time Out described it as a “blizzard of beats, bumps of white powder and punky defiance”. Rotten Tomatoes’ audience score gave it 96%.

It is a coincidence that the film has landed in the wake of anti-immigrant riots that jumped from England to Northern Ireland. Ó Dochartaigh, wearing his trademark balaclava, said fascists used misinformation to manipulate protesters. “They feel like anything on Facebook is real and it’s truth. They’re just being puppets. People aren’t thinking critically anymore. It’s so hard for them to differentiate between fact and fiction.”

Kneecap considers its own toying with fact and fiction to be a different category. Some critics are unconvinced. Last weekend, youths from a republican area of Derry attacked police in a clash unrelated to tensions over immigration. Ten officers were injured.

“Celebrating a mural of a burning police vehicle is right, but physically burning a police vehicle in real life is wrong?” Leona O’Neill, a columnist, asked in the Irish News. “Some of the burning vehicle antics is a dehumanisation of the police that only complements other players in the field.”

Ó Dochartaigh, who is from Derry, said the band did not advocate violence. “We don’t want to see anybody getting hurt. But there’s never really been any love for police in our areas for obvious reasons. They were never really representative of the community.”

Kneecap occupies a unique cultural niche as post-Good Friday agreement provocateurs, bawdy rebels and Irish language pioneers, a cocktail that has bemused and affronted the Daily Mail, among others.

Kemi Badenoch, the Conservative government’s business secretary, withheld an arts grant on the grounds that people opposed to the UK – a reference to the group’s hit Get Your Brits Out and Farewell to the Union tour – did not deserve taxpayer money. The group is contesting the decision, saying they pay UK tax and that in any case the issue is not money but freedom of expression.

Some detractors accuse the group of glamourising terrorism. Its name, after all, references paramilitary punishment attacks that inflicted grievous leg wounds on petty criminals and drug dealers – “hoods”, in Northern Ireland parlance.

But the name is ironic. Kneecap’s raps celebrate cocaine and ketamine and defiance of authority, including that of the IRA. “The subject matter that we have would have got us shot,” said Ó Cairealláin. “Young people take drugs, that’s the reality of it.”

In a surreal twist, the film includes a cameo from Gerry Adams, who is widely believed to have headed the IRA while it was kneecapping hoods. The former Sinn Fein leader denies ever being a member of the IRA.

Kneecap’s earlier work merged an assertive Gaelic identity with hood culture but the trio seem not to be authentic hoods, said Malachi O’Doherty, a Belfast commentator and author of How To Fix Northern Ireland. “They have worked diligently at presenting themselves as worthless layabouts. There’s a dishonesty at the heart of that.”

O’Doherty said he was surprised Adams collaborated with the group – and that they would want his endorsement. “Maybe what their success suggests is that hood culture and provie [Provisional IRA] culture are both now parodied rather than preserved with any integrity.”

For Kneecap, the Troubles are history ripe for subversion. There is a controversy in Ireland and Northern Ireland over crowds that chant “ooh, ah, up the ’Ra”, a catchy line from a song by the folk group Wolfe Tones. Victims of IRA violence call it hurtful but Ó Dochartaigh says time has moved on. “Half the people who are chanting it don’t know what it means. There’s no sting in it anymore. It’s just something that sounds good.”

Ó Dochartaigh, a former school teacher, credits the The Quiet Girl and other Irish language films with paving a path for Kneecap, and hails the success of bands like Fontaines DC, Lankum, The Mary Wallopers and The Scratch. “Irish music and arts just in general is having a massive moment at the minute.”

Kneecap has plans to record another album and to collaborate with indigenous language performers from Australia, Wales and north America. “If we have this monolithic one-language world where everything is the same, it’ll be very boring,” said Ó Cairealláin. “We’re on a mission to try to connect with cultures all around the world. Not everything has to be in English. I think there’s enough art in English at the moment.”