Loading There's no reason to believe things are as bad in Australia. We are not as fundamentally divided on issues such as abortion or gun ownership. Our big cities are more politically diverse. Compulsory voting nudges our politics to the centre, and we have well-funded public broadcasters that are required to strive for impartiality. But it would be naive to believe that we are inoculated from the polarisation that defines modern day America. Last Friday, when the news broke that a gunman had killed dozens of people praying in mosques in New Zealand, ABC presenter Patricia Karvelas logged on to Twitter. In one of her tweets, she praised Scott Morrison for making an "incredibly strong" statement at a press conference after the massacre. "He rightly described it as a right-wing terror attack," she wrote. "That is what this is."

Karvelas was impressed Morrison had highlighted the ideological nature of the attack. His response was altogether different from Trump's insistence, following the deadly 2017 white supremacist rally in Charlottesville, that there "were very fine people on both sides" of the protest. She was instantly hit by a deluge of criticism. "It was just one tweet about a press conference, not a dissertation about everything the Prime Minister has said about Muslims in his career. Yet it became this pile on," Karvelas says. "People were accusing me of excusing his alleged past Islamophobia. A former ABC employee told me I should get out of journalism." Ian Mannix, the former manager of ABC local radio Victoria, tweeted: "She fails to put it in context the years of hatred and racism against other people. If you can’t get this right, get out of the media."

Karvelas' conclusion: "We have lost the ability to be civil." Craig Emerson, a senior cabinet minister in the Rudd-Gillard years, also praised Morrison's response - as well as the statements by Jacinda Ardern and Bill Shorten. At an intensely upsetting and anxious moment for the Muslim community, Emerson believed all three leaders provided the strength and reassurance the moment demanded. "I was just giving credit where it was due," he says. "I copped an avalanche of criticism." The fact Emerson himself had taken a strong stand against white supremacy didn't matter. (Emerson quit as a Sky News commentator last year when the network hosted a soft interview with far-right leader Blair Cottrell.)

Like Karvelas, Emerson isn't precious and doesn't want pity. He doesn't even believe tribalism is inherently wrong or dangerous - political parties, after all, are tribes and so are our favourite sporting teams. What concerns him is "mindless tribalism", the notion that you should never break with orthodoxy or give credit to a political opponent. "This was just one isolated incident, but I do think it shows how hyper-partisan and tribal we have become," Karvelas says. "I think most people, who are busy getting on with their lives, still value civility. But there is a noisy minority that floods the internet and skews the debate." A similar point was made by Morrison in a speech this week when he said he was worried Australians are demonstrating "less understanding and grace towards others that we do not even know, making the worst possible assumptions about them and their motives, simply because we disagree with them".

"If we allow a culture of 'us and them', of tribalism, to take hold ... we will lose what makes diversity work in Australia," he said. The extreme responses following Christchurch were not limited to anonymous trolls with a handful of followers. Twitter, all too often, rewards the snarky putdown, the dogmatic over-reach, the bad-faith misinterpretation of someone's argument. Empathy won't get you much traction, and neither will nuance. Only hours after the attack, former independent MP Tony Windsor said Morrison's "dog-whistling" had "borne fruit ... not here but on a softer target". Marcia Langton, the chairwoman of Australian Indigenous Studies at the University of Melbourne, went further, saying the Prime Minister and most of his government were "complicit in mass murder".

Across the Atlantic, it wasn't only Trump, who famously called for a complete and total ban on Muslims entering the US, facing similar claims. At a vigil in New York, Chelsea Clinton was confronted by activists who said she had helped cause the massacre. "The 49 people died because of the rhetoric you put out there," one protester told her. How so? Clinton had recently criticised Muslim congresswoman Ilhan Omar for remarks that she, and many others, believe perpetuated anti-Semitic tropes. Meanwhile, Osman Faruqi, an ABC editor and former Greens staffer, was targeted for tweeting that Christchurch was "one of the worst massacres ever to occur in the west, and one of the worst massacres targeting a minority group since WW2". Among those criticising him were prominent News Corporation columnists such as Rita Panahi.

This came just weeks after the ABC aired a radio documentary detailing how Faruqi had been trolled relentlessly by right-wing Twitter users and had his phone number published online. Faruqi has now deactivated his Twitter account. Each social media platform incentivises certain behaviours, often those we would not want to encourage. Loading Replay Replay video Play video Play video Selfies tend to receive more love on Instagram than any other posts. YouTube's algorithms have pushed users towards increasingly extreme content: you start on a straightforward documentary about September 11 and, a few videos later, you're mired in conspiracy theories. Twitter, all too often, rewards the snarky putdown, the dogmatic over-reach, the bad-faith misinterpretation of someone's argument. Empathy won't get you much traction, and neither will nuance.

It's common to see Twitter users delight in seeing others get "ratioed" - that is, when someone's post attracts more negative comments than it does likes or retweets. The desire for outrage can lead people to attack those who, in fact, they agree with. Journalist Annabel Crabb experienced this when Twitter users mistakenly believed she had criticised the 16-year-old who threw an egg at Fraser Anning. Twitter is the natural home of "cancel culture", which describes the modern trend to try to extinguish people or cultural products we disagree with. It's not only notorious sexual abusers such as Michael Jackson or Harvey Weinstein who get caught in the net. Last month, US author Kosoko Jackson, who is black and gay, withdrew his forthcoming novel, A Place for Wolves, from publication.

Before his book had even hit shelves, Jackson had attracted a backlash for making two non-Muslim Americans the main characters in a story about the Kosovo War. New York Times columnist Jennifer Senior argued that Jackson's book "should have failed or succeeded in the marketplace of ideas. But it was never given the chance. The mob got to it first." After the Christchurch attacks, comedian Adam Hills was pilloried when he tweeted that he was "not OK" with Anning being egged as it would embolden his supporters. One user's succinct response: "Adam Hills is cancelled." It's all too easy for members of the mainstream media to focus solely on social media's role promoting division. We know that the stories that perform best online are often those that confirm readers' prejudices rather than challenge them. In an age of fierce competition for reader attention, it's tempting to inflame rather than inform.