'Everyone's either a magnificent hero or a sickening villain, and we know that's not true' - author Jon Ronson on Twitter shaming

"The big battle at the moment is the difference between the ideologues and humanists. It feels like the ideologues are winning on social media. Everyone's either a magnificent hero or a sickening villain, and we know that's not true," he said at an event hosted by Mindshare chief executive Helen McRae.

Ronson referenced the example of Justine Stacco, a PR consultant who last year tweeted the message: 'Going to Africa. Hope I don't get AIDS. Just kidding. I'm white!' Stacco published the ill-advised tweet to her 170 followers just prior to boarding a long-haul flight to Cape Town. In the following hours, she was retweeted by a journalist at Gawker and went viral, prompting vitriolic messages from around the world, including calls for her to be sacked from her job and rape threats - all before her flight had landed.

"While she slept on a plane, Twitter took control of her life and dismantled it," Ronson said. "People around the world thought that it was their duty to get her fired."

"The anger turned to excitement when we realised Justine didn't know [as she was on a plane]. People were delighted. They worked out what flight she was on and looked at her fligher tracker. The hashtag #hasjustinelandedyet was trending.

"This isn't social justice; this is a cathartic version of social justice."

The echo chamber of social networks, particularly Twitter, makes them prime environments for targeting individuals in this way, he said.

"One of the problems with social media is that it's a mutual approval system. Tech utopians will say it's like democracy, but it's not - it's the opposite of democracy. When we're approving of something and someone gets in the way, they are screened out."

He made the point that nobody stood up for Stacco for fear of repercussions. When a journalist suggested she thought the tweet was not intended to be racist, she too was met with a string of abusive messages.

"I come from a world of curiosity and nuance, and those things are now considered weaknesses. Something weird happened with Justine Stacco. Calling for a bit of patience to hear what they have to say is considered a weakness. Context is considered anti-ideological."

Twitter has been "terrible" at addressing the problem, he added. "They are bringing in groups like Feminist Frequency but I don't think that totally adjusts the problem, because this is an umbrella problem. If you only target it as an ideological issue, that's not going to solve the problem.

He said that shaming can, however, be justified when it is used to attack systemic failures, rather than individuals.

"When you're attacking bad ideas and systemic failings, shaming is good, for instance #oscarssowhite and Everyday Sexism. Everybody gets to see the everyday sexism, yet we're not tearing someone apart."

Discussing a recent interview with Monica Lewinsky, which ran in the Guardian and which has accrued over 70,000 shares since it was published on Saturday (16 April), Ronson said that in order to reclaim her identity, Lewinksy, who had been vilified for so long, had to 'integrate her experience'.

"She drifted to London and her lecturer [at LSE] said 'when power is involved there has to be a competing narrative, and you don't have one'. She recreated her identity. She had to reclaim her identity by integrating her experience. As soon as she assimiliated her experience, she claimed it back."