This post offers a brief and partial answer to the question: "Why is it that humanity must suffer so deeply and yet those who cause that suffering can bring themselves to inflict such harm on others?"
There is what I call a disjunct in the minds of those who can make others suffer... it happens this way:
It starts with fear. If you mix that fear with high intelligence (which most of them have), the fear is amplified very drastically. Their knowledge of the world around them gives them even that much more to fear, because they are so intelligent. The 'snake' begins to eat it's own tail and causes begin to create themselves anew - with each new coil of the snake their fear manifests its own reasons to increase!
That fear leads to their need to control in order to compensate for it. They notice though that most other people are trusting. They convince themselves (wrongly) that those trusting people around them are less sophisticated than they (i.e. they become an exception to themselves with respect to the rest of humanity), otherwise those others would need to fear and need to control as much as they do.
Ergo: those who are trusting are schmucks or 'makes' that are asking to be screwed.
In order to counter this distortion they sense in their view of the world, they tell themselves they are 'special' and lie to themselves reaching hegemonic conviction with statements like: "The ends justify the means." or any other permission to continue making their world 'safe'. The truth is that the ends are determined by their means. (destructive means ALWAYS lead to destructive ends - it's a natural law)
This 'cancer' begins to cause a feedback loop in their psyche. They need to 'touch' and 'mark' all things they purvey to make themselves 'safe'.
It metastasizes into a need to even control and pervert everything and everyone around them. They can't even have sex without some sort of perversion. It's usually they who become pedophiles.
Their obsession with control mechanisms forces them to confuse chutzpah with ruthlessness and bravery with cruelty.
It is also they who 'paint' our skies with artificial clouds to witness their 'mark' in assuaging their fear and to express their thirst for more control.