In the nearly two years since the country branded Eleanor Catton a traitor, most of us will have forgotten about the furore dubbed Cattongate.

We'll have forgotten that she was called an ungrateful hua.

We'll probably even have forgotten that her "traitorous" criticism of our Government at an event in India was really no worse than what most of us say here at home.

Eleanor Catton hasn't forgotten any of it.

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It left her so depressed she couldn't leave her house.

She painted rooms and built a miniature doll house to distract herself.

The Luminaries author told me she feels "quite ashamed" of New Zealand's reaction when people overseas ask her about it.

She said it was disproportionate and "aggressive".

"That didn't seem like a debate to me. That didn't seem like people were really talking about something meaningful.

"People were really angry on both sides. And nothing really changed."

The kind of national shout down we inflicted on Eleanor Catton is happening more and more often.

You can measure this growing moral outrage in the frequency of the word "disgust".

In the single minute before I searched "disgusting" on Twitter, 16 people had used the word on their tweets.

Apparently men are disgusting, Washington's political establishment is disgusting, the online right wingers who call themselves the Alt-Right are disgusting pigs, and there's consensus Donald Trump and his staff are disgusting.

In New Zealand, Brian Tamaki is disgusting, Aaron Smith was disgusting and, depending on the latest headline, John Key, Nick Smith and Paula Bennett take turns being disgusting.

The problem is all this heady emotion is driving our political decision-making these days.

We're living in the era of post-truth politics.

We no longer use truth or facts to make up our minds because, for years, we have seen the same set of facts skewed this way and that to prove completely opposing points.

So, we instead base our decisions on emotions.

That explains why, even though the UK public knew Brexit campaigners had lied in their claim the UK pays £350 million to the European Union weekly, people ignored it and voted for Brexit anyway.

It explains why, even though several women accused Donald Trump of sexual assault, people ignored it and voted for Trump.

In part we can blame social media.

Our google, Facebook and Twitter profiles are set up to make us less tolerant of divergent views.

When you like a news article on Facebook, the algorithms will feed you more of the same, reinforcing whatever view you already hold.

When you choose who to follow on Twitter and who to befriend on Facebook, you're drawn to people you agree with and they reinforce the views you hold.

And so, you create an echo chamber that may be so strong, you may end up like my left-wing friend who says she was genuinely surprised when National won the 2014 election.

Everyone she knew and spoke to was voting Labour/Greens.

And in the echo chamber, you won't meet the kinds of people you find disgusting.

You won't discover that even so-called disgusting homophobes and racists have kids who love them and grannies they look after.

In the long term, if we don't talk to the people on the other side of the Facebook algorithm, we'll keep shouting people down, putting them through hell then moving on to our next target.

We'll end up as divided as the US, surprised by and refusing to accept the election outcome.

We have a tough time ahead of us in politics in New Zealand.

Soon, we'll need to have grown up conversations about questions like how many immigrants we want.

We need to drop the fighting talk for that.