I think that's something shared by a lot of us. I believe that woof that had either high functioning autism or a schizoidal personality disorder. He was hyper-introverted, either ignorant of or disinterested in social norms, and seemed to have unorthodox and deep interests that delve into the special interest territory.What I found most interesting in Woof's faux-apology was how he established that dogs lived a rough life around him. They could be killed by neighbors or sickness due to lack of proper health care. So for all his talk about how much he supposedly loves dogs, he was exposed to a lot of dog death. This could have contributed to being desensitized to it before he started seeking out zoo porn, as dogs were apparently seen as disposable, in a sense.
This is obviously not an excuse for what he did, but a possible contributing factor in what might have lead him to do this in the first place. I also wouldn't be surprised if he suffered head trauma as a child or had a poor or abusive relationship with his parents.
I must admit, I am morbidly curious as to how somebody winds up doing things so horrible to poor little puppers.
For the latter, this includes animals, but it also seemed to include fascination for Nazi era Germany and period German military hardware, and he seems to have devoted a lot of time to making crib sheets for alt-history tanks and armaments.
The following is conjecture, and is based off of conversations with the leakers, inferences from broader research, and the confession.
I think woof initially got into this as a plain zoophile (as if such a thing could be considered 'plain') who was fascinated and disgusted by why people would be aroused by inflicting such cruelty on animals. He wanted to understand why this was a thing, and ended up finding people who were into it and getting zoosadist porn to try to investigate the phenomena and he may of initially been claiming he wanted to send these people over to the authorities. However, I think he a) was initially drawn to investigate this because he had a hitherto hidden proclivity towards sadistic sexual practices that he was either unconsciously or quasi-consciously exploring, and/or b) found himself overwhelmed and aforementioned sexual deviance indulged by the zoosadist porn, and decided to produce his own.
Pernas is a desperately lonely and weird man. His only substantive companions seem to have been animals throughout his life. I think he had no moral force or support network to stop him from retreating from the world and entering a vicious spiral of depravity - his job seems solitary, and his private life utterly dreary. So, with nothing around him, he just fell down the rabbit hole once he discovered that this initially disgusting thing was something he found himself aroused by.
I think woof was a landmine; if triggered just right, he would go off and indulge his deviances. What triggered this particular landmine was curiosity.
If there's a lesson to be learned from all of this, it's this: discover your own demons before looking into someone else's.