Honestly, I think it is this perspective that gives me pause when I try to enjoy true crime. The people written about in true crime reporting are such extreme cases, and their situations are rendered in such extreme terms. It's fascinating stuff, and of course people who commit evil on a massive scale are a subject worthy of discussion. But most crime is nothing like what we learn about in true crime reports. Most of it is far less sensational and far less driven by what we might want to call evil.
Most crime is contextual, and social, and driven by a ton of external factors like poverty, racism, sexism, and other systemic forms of hate. David Foster Wallace is no Ed Gein or Golden State Killer; he was a pretty typical product of his sexist, wealthy, white upbringing. Mary Karr might not have abused people the way he did, but lots of wealthy white men like him do, and plenty of white women like Mary Karr aren't as lovely as she is, and do a ton to abuse the people of color around them. None of this is because they are uniquely evil, it is because of their privileges and the values society taught them to adopt.
So when I look at harm being done in the world, I just don't think focusing on othering the people who do harm is productive. I am much more interested in the contextual factors. That doesn't excuse what DFW did. It just means that if we want to prevent future DFW's, we stop focusing on evil as a unique thing, and instead see how our society and its systems are evil.