On 25 March, Bill Mitchell posted a photograph of David Hogg on Twitter, along with the following fictional exchange:

Hollywood agent’s office:

Secretary: “Central Casting called. They’re looking for a Damien, Children of the Corn, Hitler Youth-type to cast in a flick about an Orwellian future where fear and emotionalism is used to subjugate a free people.”

Agent: “Nailed it!”

David Hogg is a survivor of the Marjory Stoneman Douglas High School shooting in Parkland, Florida, on 14 February. He has since become a vocal opponent of the gun lobby, along with several of his fellow pupils. He is 17 years old.

Bill Mitchell is an American radio talk show host, a Trump supporter who wears a ring with, apparently, “Make America Great Again” inscribed upon it. In 2016, he was named by the Massachusetts Institute of Technology’s Media Lab research unit as the top-ranked “ordinary citizen” – behind politicians and influencers – responsible for helping Donald Trump get to the White House. He has 347,000 Twitter followers. He is 57 years old.

This is by no means an isolated incident. The lie that the Parkland kids who have decided enough is enough are liberal shills, left-wing stooges, “crisis actors”, has been trotted out relentlessly practically since the gunshots from former student Nikolas Cruz’s murderous rampage around the school were still ringing around the campus.

Even the website Snopes, which for years has debunked (or stood-up, where appropriate) internet rumours, stories and conspiracy theories, was moved to put up an entry this week on Hogg and the claims that the teenager had actually attended high school in California, not Florida at all. The disinformation stemmed from a poorly-photoshopped hoax picture purporting to be from the yearbook of a West Coast school. That it was a very low-rent attempt – Hogg’s photograph is actually taken from the Marjory Stoneman Douglas yearbook.

It isn’t just Hogg who’s come in for flak from conservatives and the alt-right, of course. Emma Gonzalez is another Parkland survivor whose emotional speeches have helped galvanise a generation into protesting and marching for stricter gun controls in the US.

At the weekend, a Twitter account for Gab: The Free Speech Network, posted a video of Gonzalez ripping up the American constitution with the message: “Not gonna happen”. It was, in technical terms, a more proficient attempt than Hogg’s high school yearbook, but it was a put-up job nonetheless. Gonzalez was actually ripping up a shooting target.

A fake video of Emma Gonzalez ripping up the American constitution went viral (Getty) (Getty Images)

“This is obviously a parody/satire. You’re all mad because it’s believable, isn’t it? That’s the best type of satire. It’s a comedic reflection of reality,” Gab tweeted the next day. But the damage had been done as the video went viral, pushed around the internet by people who believed it.

Hiding behind claims of satire is the get-out clause of these people. Mitchell’s slur on David Hogg was framed as an imaginary conversation in a Hollywood agent’s office. “But it’s just a joke!” they cry, even as they watch their supporters fan the flames of the bonfire of reputations they’ve put the match to.

It’s no coincidence, nor surprise, that the right ramped up its campaign against the Parkland survivors and the protest they have set in motion on the weekend that the March For Our Lives event took place in Washington DC. An event which, according to organisers, had 800,000 attendees, far outstripping Donald Trump’s inauguration crowd just over a year ago.

Perhaps the American right is running scared by what Parkland has started. Mostly, after a shooting atrocity in America, gun control is put on the agenda for a few days, then it starts to fall down the media agenda. That isn’t happening with Parkland. These pesky kids are refusing to go away.

But here we come to the nub of the problem. This is what the Parkland survivors are: kids. Yes, they are kids with a mission, kids with a message. But kids all the same. And to see someone like 57-year-old Bill Mitchell punching down on the internet on a 17-year-old who has survived one of the worst mass shootings in American history is just despicable.

Grown men taking on kids. Adults making up lies about children. People who should know better sitting in their rooms and faking photographs and videos. Of children. Then posting them on social networks.

“But it’s satire! It’s just a joke!” That won’t cut it any more. Those behind these smears really should be taking a long, hard look at themselves and asking if this is really what’s going to make America great again. Those who gather up these steaming, defamatory turds and run off, giggling, sharing them with their friends, ought to be thinking just a little bit harder about what they’re picking up off the alt-right internet floor, and considering that when you pass along shit, then it sticks to your hands, like blood and Lady Macbeth.

March For Our Lives had 800,000 attendees, far outstripping Donald Trump’s inauguration crowd just over a year ago (Getty) (Getty Images)

In 2004, a lawyer from Ohio digitally manipulated entirely innocent images of children to make it look as though they were engaged in pornographic acts. Dean Boland presented the images at three different trials in his capacity as an expert witness acting for the defence of people accused of possessing child pornography. His argument was that digital photography editing was so sophisticated that it was almost impossible to tell whether images were real or faked.

When the parents of the children in the images – which were taken from stock photo websites – found out about the pictures, they sued Boland. The case was initially thrown out, then an appeal was lodged and it was found in favour of the parents. A second appeal against the ruling, from Boland, was dismissed in 2012 and he was ordered to pay $150,000 (£105,000) each to the families of the children.

The point is, in US federal law, there is protection for children whose images are manipulated for pornographic purposes. On an ethical level, is it so very different what these grown men are doing to the Parkland kids? Boland’s argument was that no children were actually harmed in the creation of his images; perhaps those who doctor videos of Emma Gonzalez or high school pictures of David Hogg might offer roughly the same arguments.

Indeed, the actual real-life fall-out for the Parkland kids might be worse. In the UK, every trainee journalist has the definitions of defamation burned on to their central cortex from a very early age. A statement can be said to be defamatory if it exposes the subject to hatred, ridicule or contempt; causes the person to be shunned or avoided; lowers the person in the estimation of right thinking members of society generally; disparages the person in his/her business, trade, office or profession.

Even with the satire/fair comment defence available, those images of Hogg and Gonzalez could conceivably be grounds for bringing a case of defamation in the UK, should they wish to. But defamation laws in the US are different and messy.

There is a federal law governing libel and slander, but it’s strongly tied to the First Amendment which protects freedom of speech. A plaintiff bringing a defamation suit must prove that a statement is false, has been published or broadcast maliciously, and has caused them material harm. It’s a tough nut to crack in the US, where opinion is strongly protected under the First Amendment. And, hey, if that video you posted is just satire, then that’s not malicious, is it? What material harm is there in a joke?

But it doesn’t really matter whose side the laws of defamation fall on. This isn’t about what’s legal, it’s about what’s right and what’s proper. It’s about what’s appropriate for adults to be doing when directly referencing children online.

As the movement given momentum by the Parkland kids continues to grow – and grow it will, now that this ball is rolling downhill – they can probably expect more of this. They can probably expect worse. Doctored videos from “free speech networks” such as Gab and smug tweets from “voice of America” radio talk show hosts like Bill Mitchell might only be the tip of the iceberg as the alt-right gets increasingly twitchy. And we all know that the bit of the iceberg we see hides something big and ominous and dark, down in those depths.