I think most people are taught to communicate with people they have problems with. Communication is key to any relationship; you don't need to be a psychotherapist to know this. In the US, proper communication with roommates is a basic social skill that most people learn in college.

You can't expect to do nothing in a bad situation and then complain when it gets even worse. If you read a post about a guy complaining about loud neighbors, you'd be pretty skeptical if he didn't mention "asking them to turn the volume down" even once.

There's a lot left out of this story. Did OP even bother confronting the roommate about his problems? Did OP just remain passive-aggressive and sulk the entire time he lived there? I'm curious why OP left out that side of the story. You can't really hate on the roommate that much if OP didn't even vocalize his concerns to him.