God, I'm glad they caught him. I mean, I'm well aware there are so many people out there who would act on depraved fantasies if they could or if something triggered them, but when I read he'd fled to Europe I was completely irrationally afraid for about ten minutes. And then it slipped my mind again. I am Suisse cheese.

As for the interest in snuff: yes, it's quite unethical. We all have deeply unethical impulses, that's why we invented ethics. And it takes some years for our conscience to develop enough in order to understand why something is unethical, rather than simply know it. My guess is you've always known it's wrong to want to watch another human being die, and that was the initial attraction. But as you get older and your ties to other people get firmer and your brain is fully formed, you start to really understand what it means, what it would do to you if it was a loved one of yours, like you mentioned.
And part of being human is being curious. It's basically what distinguishes us from so many other animals: we investigate everything, even if it's really silly or incredibly dangerous. We NEED to know. So... 's all perfectly human. I guess that means we just kind of suck, but at least we know we do, and so we invented a whole lot of fail-safes to make sure we protect the world as much against our suckiness as we can.
And occasionally, all the fail-safes actually fail. Like in the case of this guy.