I think i've seen this before and it lterally made me sick to the stomach.
When it comes down to it, some people are just evil. Whether they've had a shit life or a good one, or whatever their excuses are. They were born evil. No-one like that deserves to live, and take my word for it, I would go to prision for life if you would just let me murder people like this, and it would all be worth it.