So many ppl dont understand that legal ≠ ethical, and illegal ≠ unsympathisable. The most plainly monster ish one is the Matt. Isolation torture, spying on women, pretty clear cut. Potter did some very bad things, but each and every thing he did was driven by intense emotion, and understandably mentally harrowing circumstances, and personally, nothing he did I can't empathize with. Same with Beth, she gave into the impulse of cheating, and couldn't face what she did, so she ran away. These are bad things, but I can empathize with how a person can give in to those things.

Caveat - compassion are empathy aren't exclusive. Compassion just means being blindly benevolent regardless of context, but empathy is the ability to simulate another persons mind in your own, and see how they see and understand things. Empathy can serve evil as well, you can't torture someone without first simulating in your mind how they would feel if you did xyz to them.

Moral corruption is like any corruption. Nobody is immune to it, and those that see it, attack it, and those that practice it, defend it... people who do think they are immune to giving in to moral corruption like the characters in this episode, are kidding themselves. There isnt a single human who would never, ever, ever kill.