I think there's a bit of blurring between fact and urban legend, of incident and potential incident.
These days, with the ubiquity of video recording equipment - even on a mobile 'phone - combined with the many non-professional platforms they can be displayed on, is it any wonder that such content gets "leaked"?
Murderers - especially serial killers - have always 'displayed' their gruesome handiwork. Christie using a human femur to repair his garden fence was almost subconscious. Photographs of the victims have been around since ownership of cameras. Tape recordings and photos of the Moors Murderers. Videos by such as Lake and Ng. All are 'created' by the killer. These records are created by a killer for their own gratification, in one way or another. Even phone footage of someone being assaulted and end up dead gets uploaded. If they are circulated in the media, dark web or not, it is for the titillation of the viewer.
There are many crime scene photos of the mutilations of the Black Dahlia, Jack the Ripper and so on. These, in effect, are "public record". If a person got their jollies from seeing real death and torture, it's not hard to find - regardless of the morality.
Thus, I suggest, that if there was a business out there which kidnapped, tortured and murdered people for the gratification of a particular group, they'd have to make it really pay. Special effects now are such that you could fake it, say it was real, and still get paid. If you consider that the risk to The Organisation was higher (by repetition, resources and personnel) than if one rich bloke wanted to watch someone tortured, one must ask - in a cold, calculated way - what kind of a business plan is it? And is this plan viable?
As I said, the platform and technology is there for an increase in recorded abuse. So is it a case that increased availability means increased ... er ... exposure? Or is the increased exposure a sign that there is a shadowy cabal who makes money from pervert rich guys by killing? Even dark web shows stuff that is graphic, horrific and gruesome ... but is it only showing stuff that has been censored by the mainstream and not created specifically for the depraved?
Think about it.
Produce a high-quality film about a documented killer, as yet uncaptured, and do it in the now done-to-death style of 'found footage'. You could sell it to a rich sicko. You could upload it to the dark web. How, exactly, do you realise your investment? Even if your true nature - the fakery - is exposed, you've sold it to the rich sicko, at no real risk to yourself. And no one is really dead.
Yet.