Once upon a time, not all that long ago, it was unusual to hear hundreds of people claim that children deserve to die. Over the past ten months, six migrant children have died after being detained by United States border authorities, and a remarkable number of Americans don’t really mind. Last month, after a few casual, carefree clicks on Twitter, I found myself staring in awe at post after post justifying, celebrating, or dismissing the death of immigrants.

Thanks to the internet, I now know that there is a person in the world who can read about the death of ten-year-old Darlyn Cristabel Cordova-Valle – who travelled from El Salvador to the US in the hope of reuniting with her mother – and reply “bummer”.

Thanks to the internet, I know that a person who proudly declares themselves “deplorable” can be confronted with the death of eight-year-old Felipe Gómez Alonzo – whose greatest wish was to own a bicycle – and callously declare “too bad”.

And thanks to the internet, I know that there are dozens of people who can look at a photograph of the innocent, smiling face of two-year-old Wilmer Josué Ramírez Vásquez, who is the fourth Guatemalan child to die in US custody since December, and mourn instead for “taxpayer expenses”.

In the decade prior to these deaths, no children died while in the hands of US Customs and Border Protection. From January to April 2019, over 300,000 people were apprehended at the US-Mexico border, and the detention facilities where they are held have been routinely criticised by human rights experts. I understand the impulse, if you are a Republican, to point out that detention conditions under Obama were inhumane too. But I can’t understand how party allegiances and political point-scoring override something I once thought was undeniable: it is a bad thing for children to die.

It is no longer unusual to see unthinkable thoughts proudly shared on the internet. Online evil is nothing new, but where once it was contained in corners, it is now everywhere, all at once. In the past, morbid curiosity might have driven us to misogynist “incel” forums or neo-Nazi websites, and we’d gawp like intrepid explorers at the unrecognisable poisons within. Now, the world’s most popular websites are plagued with abhorrent posts that are shared and received as though they are normal.

I’m not talking about trolls, or Russian bots, or the countless people who gleefully seek to antagonise online. I’m talking about ordinary people sharing their ordinary thoughts. I’m talking about the secret, 10,000-strong Facebook group for current and former border patrol agents where Mexican migrants were called “subhuman” and “shitbags” before it was discovered in July. I’m talking about people who proudly declare that death is a deserved punishment for an immigrant who dares to dream of a better life; people who believe the accident of a child’s birth justifies the tragedy of their death.

What are the consequences of evil being made mundane by its daily appearance online? For me, it’s a feeling of overwhelming sadness, but a sadness I quickly seek to shake away with the next dog gif or witty tweet. I’m sure many people find it overwhelming and mentally devastating, but it’s scarier to think of many more who become desensitised to our new normal.

Perhaps it’s a good thing for evil thoughts to become visible online. It’s possible that these posts provide a deeper understanding of historical human atrocities. Maybe it’s valuable to see things starkly in black, white and Twitter’s blue – to be equipped to provide an answer to our descendants’ murmurs of “how did this happen?”. It might be, but I can’t help feel this also provides us with an easy out: the ability to caricature our political opponents as uniquely evil people, rather than ordinary people with evil thoughts.

In their book Evil Online, ethics professors Dean Cocking and Jeroen van den Hoven argue that the internet has turned “otherwise ordinary, pro-social people” towards wrongdoing, building upon Hannah Arendt’s theory of the “banality of evil”. The academics argue that the internet undermines our societal values that maintain order, and online spaces plunge us into a “moral fog” that means we are unable to see the consequences of our digital actions. It is not really, then, that the internet allows us to say things we would never have dared say before – it also makes us want to say them in the first place.

It is terrifying to live in a time when the Overton window – the range of acceptable public ideas – has not just been swung open, but smashed. Across the globe we see that formerly fringe beliefs are now the matter of mainstream public policy, with fascist movements gaining ground across Europe. The people have emboldened the politicians, and the politicians in turn have emboldened the people, and our norms have become so skewed that this July it was a matter of genuine debate whether telling ethnic minorities to “go home” is racist.

Every day on the internet I can click on a news story that tells of something indisputably bad, and see tens of gleeful comments that make my stomach turn. It’s hard not to look at these and feel that the internet is a failed experiment – that we should switch it off and start again. But in lieu of a solution we continue to log on, our own moral compasses slowly shifting along with the tide.

Confronted with the passing of six helpless migrant children, I can understand how basic human psychology might lead people into denial, or whataboutism, or cries of “fake news”. I understand that no one reacts perfectly to tragedy. But I didn’t understand, before the internet, that hundreds of people could respond to children’s deaths with the infamous sentiment of a Melania Trump jacket: “I really don’t care, do u?”