Kneecap are no strangers to controversy. They rap about drugs – and are named for the notorious punishment meted out by the IRA at the height of the Troubles to drug dealers, while one of the trio wears a tricolour balaclava.

But for their fans – especially those “ceasefire babies” who, like them, grew up in the aftermath of the Good Friday agreement – they are a breath of fresh air. They play with Republican imagery – often mocking it – but are staunch in their nationalism, explains the Guardian’s Ireland correspondent, Rory Carroll. A semi-fictionalised film about their origins won a Bafta. And they have won more praise and fans for their unusual and political choice to rap in Irish.

The Irish writer and editor Roisin Lanigan tells Michael Safi what that means. “Irish has always been so denigrated,” she says, that hearing it used in hip-hop “does feel important and just cool – I didn’t realise that Irish could sound like that”.

But this year Kneecap have found themselves in a storm more intense than any they have weathered before. Last month the trio played Coachella and led the US crowd in chants of “Free Palestine”, making clear their view that Israel is committing genocide. Afterwards older clips from concerts emerged of band members appearing to shout out support of Hamas and Hezbollah, and call for the deaths of Conservative MPs. Counter-terrorism police have confirmed they are now investigating the band.

Now politicians have condemned the band and even called for them to be dropped from festivals. In response, musicians from Pulp to Massive Attack have written a furious response saying politicians should not be interfering in musical expression. Meanwhile the hip-hop stars and their manager have said the attacks are confected by those who want to demonise them, and that this is a deliberate distraction from the plight of people in Gaza.