Someone in Florida was sentenced to five months in prison this week for threatening the father of one the children killed at Sandy Hook elementary school. There’s a whole big conspiracy theory about Sandy Hook.

[Leonard] Pozner has spent years using every tool at his disposal to scrub the online record of his son’s memory clean of videos suggesting that Noah and his surviving siblings and his parents are actors perpetrating a massive conspiracy against the American public. Pozner has made some progress in defending his family against these lies, but he said that countering hoaxers is still an uphill battle. Big tech companies such as Google, Twitter and Facebook are doing far too little to deter the conspiracies, harassment and hatred that flourish on their sites, Pozner said.

While these companies have been talking publicly about confronting fake news, “They really don’t do that much. They can be doing a lot more – especially Facebook. It really turns the other way.”

He said tech companies that allow the spread of conspiracies and hatred, including Islamic State propaganda, “have blood on their hands”.

Why would there be a conspiracy theory about Sandy Hook?

Pozner’s six-year-old son, Noah, was murdered alongside his first-grade classmates in Newtown on 14 December 2012. Pozner’s young son was one of 20 first-graders and six educators who were shot to death in a small suburban elementary school by a troubled local man with a military-style rifle in one of the most shocking mass shootings in US history.

But in the early stages of mourning their murdered children, the Pozners and other families of victims had to confront an extra burden: accusations that their children were not dead, and that the tragedy that upended their lives was all a fraud designed to undermine Americans’ gun rights.

Oh. That. Good god.

While he had no exact data, Pozner said he believes there are “tens of thousands” of conspiracy theorists globally who believe that mass casualty attacks such as Sandy Hook, the Boston Marathon bombing and the 2012 mass shooting at a movie theater in Aurora, Colorado, are hoaxes.

As more and more people join social media sites, Pozner believes the problem is growing more acute – and more people vulnerable to conspiracy theories are exposed to the “contagious addictive content” that spread hoaxes like viruses across the internet.

Pozner, who once listened to InfoWars’ Alex Jones before Jones became a Sandy Hook conspiracy theorist, said that people were drawn to hoaxes for different reasons.

Some “have nothing else going on in their lives and this gives them a sense of community, a sense of identity. It’s like a cult,” he said. Others are drawn to feeling “smarter” than the people around them who do not believe the conspiracy, thinking, “Oh, I’m awake – you guys are not awake.”

That works going in both directions though, and if you do it in the other direction, at least you’re not harassing the families of the murdered children.

The Honr Network, the organization Pozner founded to hold hoaxers accountable for their behavior, now has about 300 volunteers who help monitor hoaxer content online.

It is a gruesome world to confront briefly, much less over and over again. Hoaxers, for example, will share videos of Boston Marathon bombing victims having their limbs blown off, and then debate whether the color of the blood in the footage is realistic, or look for evidence that the person in the footage whose limb was just blown off was already an amputee who is now faking a new injury.

The long fight to use copyright protections to remove family photographs of Noah and his surviving children from posts full of wild conspiracies has left him frustrated at tech companies, who he said often push back or simply refuse to take down content related to his young children.

“If you become the victim of a crime, shouldn’t you be protected by society somehow? Shouldn’t society hold you up when you’re kind of weakened? That’s not the case right now. If life has thrown you a curveball and you’ve been knocked to the ground, YouTube and Google and Facebook think that others should be allowed to kick you while you’re down as much as they like, and they’ll protect those people’s right to kick you.”

Yes, they do, and they will.