I mean, you guys are missing that anyone can be a psychopath. All it requires is the death of empathy. Killing your fellow man is not physically hard in a modern society, it’s the desire to do so that most, thankfully, lack. Walter is not harmless because he is sick, he is dangerous because he is willing to commit violence for personal gain or to eliminate a perceived threat.

At least most lack that will in person. Supporting the death of others from the comfort of your living room is rather common.