The thing about the teenagers stabbing their mothers is that its easy to dismiss them as not being part of regular humanity. "Inhuman" behavior, as we like to call it. By "worst aspects of humanity," I mean the worst aspects of normal humanity, when we regular, normally decent and good folk show the dark, nasty parts of ourselves we like to keep silent. As people like to say, be exposed to every single one a friend's deepest and most private thoughts, and you probably won't like that person anymore.
"If this is supposed to be some allegory for internet criticism, it's perhaps the most epic attempt yet to equate comic readers who said your comic writing sucked shit to serial killers that there has yet been."
The serial killer in the story is the guy receiving the criticism.