First there was a moment of stunned silence. Then, in the Sala Grande, the main screening hall of the Venice film festival within the Palazzo del Cinema, the audience stood almost as one and turned to applaud the film-makers for 25 minutes. This was reported by Qazaqyia.kz citing The Guardian.

The film the audience had watched for 80 harrowing minutes was the Gaza documentary NAZA, which has been produced by the Guardian. The film's title comes from an Israeli military acronym used euphemistically to refer to the civilians expected to be killed in a military attack.

Unfolding against the background of Tel Aviv at night, the participants – intelligence officers and other soldiers – describe a series of systems, some powered by AI, that select the thousands who should die in strikes, often at night and surrounded by their families.

Perhaps most challenging for Israel's political elite is that it is a story told exclusively in Hebrew by 24 anonymised Israeli military insiders, many of them from elite units. The documentary depicts a wide variety of viewpoints that all lead to the same conclusion: participation in a programme of mass killing where there were few boundaries between combatant and civilian, in a war where more than 73,000 Palestinians have been killed. Some describe being shamed by their experience. Some are neutral. Others describe excitement, and a sense of "fun" as they justify their actions.

It will open in US cinemas from 30 September, with international distribution plans to be announced shortly. The ripples of ovation gathered in volume among the few who have seen the film before its New York premiere, but in Israel the film provoked a very different response.

Rightwing political figures have rushed to accuse its directors – the Oscar-winning Israeli film-makers Yuval Abraham and Rachel Szor – of "treason". The Israeli prime minister, Benjamin Netanyahu, who has long harboured an antipathy to critical media, declared on Wednesday he would seek new laws to strip citizenship from people who he said "smear" Israeli soldiers.

Demonstrators and members of far-right groups went further still, calling for violence against the pair and the demolition of their homes. Outside Szor's parents' house in central Israel, protesters called for the "death penalty for traitors".

An editorial in the left-leaning newspaper Haaretz warned that their lives were credibly endangered. Dozens of human rights and peace organisations in Israel rallied to defend the film-makers, as did international press freedom organisations.

The whiplash ferocity of the response, even in the midst of a febrile election campaign where Israeli attitudes to the war in Gaza are a central issue, has surprised even those in the Israeli leftwing and human rights community who have long been on the receiving end of such denunciations.

The pushback to the documentary is both a testament to its power and evidence of how the Israeli right is exploiting a film, as yet unseen by most, to craft its own version of what it says it represents.

Critics in Israel seized on the longstanding idea that Israelis should not criticise their country in front of foreign audiences. Ofer Winter, a controversial former rightwing army officer turned politician, told an election rally for his People of Israel in Rishon LeZion: "An Israeli citizen, a Jew, receives thunderous applause for going out and smearing and defaming his own people. I understand that you are afraid to return to Israel," he taunted the directors. "You are right. You have nothing to return to. It is a disgrace and a shame to return after you spat in the faces of your own people."

The rightwing journalist Yehuda Schlesinger of Channel 14, a station regarded as being a mouthpiece for Netanyahu, went further still, saying Abraham and Szor should be "pursued" and "hunted", prevented from returning to Israel, and describing the ovation in Venice as "25 minutes of antisemitic applause".

By Wednesday, Netanyahu had decided to weigh in, announcing he would promote two bills to legislate against the "defamation" of Israeli soldiers and the state of Israel. "We will revoke citizenship for anyone who defames IDF soldiers around the world – he will be deeply hurt in his pocket."

At points, the threats of violence have been realised. On Wednesday, the journalist Haggai Matar, a director of the left-leaning independent +972 Magazine and Sicha Mekomit (Local Call), where Abraham's first reporting on the allegations appeared in collaboration with the Guardian, said their offices had been broken into by rightwing activists who had filmed the intrusion.

"The discussion about NAZA has been a million times more prominent than the UK sanctions announcement," said Dahlia Scheindlin, an Israeli political and polling expert who writes a column for Haaretz, adding that the right was exploiting the current inability of Israelis to see the film and make their own judgment. "While it is unseen, it can be turned into something electorally potent that at present Israelis aren't able to demystify."

The film has also arrived in the midst of a markedly worsening atmosphere towards dissenting views, acute since Hamas's deadly attack on southern Israel on 7 October 2023, with the film challenging a long-held