A potentially interesting topic, but the style in which this article is written is very irritating. It's trying to put words into the reader's mouth, and most of the "replies" are rather insulting and overtly stereotypical.

Back onto the topic itself - some runners run away from something bad in their lives, or have adopted addiction to running to replace some other addiction, usually drugs or overworking. I know a few like that personally, and they are indeed unhappy.