First off, yes, those sorts of videos do exist. Boy do I (and a lot of traumatized journos) wish they didn't. And yes, there are scary groups of horrible people doing exactly these sorts of terrible things. It's one of the reasons that, for example, those ISIS fuckpantaloons are so hated. Though there are a whole bunch of genocidal asshats in sub-saharan Africa and south-east Asia that also get their rocks off doing that sort of shit and then posting it online, too.
As for the ""snuff video" hysteria of a few decades ago"...you know, that wasn't entirely overhyped. I can remember one video in particular that I ran across that I couldn't close fast enough. What I saw still haunts me in the dark hours of the night as I lie in bed trying to sleep...and I am pretty sure that having closed it less than 10 seconds in to a two minute .avi, I missed the really horrible stuff. I don't buy into the idea that organized crime was depopulating small towns to make snuff porn for the deranged westerner or any of that...but you know what? There's some really sick fucking shit on the internets.
Never, ever doubt the depth of man's inhumanity to man.
Secondly, regarding your "YOU HAVE NO FUCKING CLUE WHAT HELL I HAVE EXPERIENCED. And it is not for you to know, either. But I do know, from first hand experience, what lows people are capable of." diatribe...put simply: I don't believe you. If you had seen the lows of humanity I'd fully expect you to be capable of empathy towards those who have also had to deal with witnessing traumatic events, and your posts indicate that you don't have that empathy.
Unless, of course, you're a sociopath. They tend to be able to take a "just suck it up and move on with it" approach to witnessing trauma. I'd hardly call that a positive thing, but it is what it is...