The article didn't make any religious argument for the command line opposed to a GUI. His background is the opposite of yours. For him, relying on the ease of a graphical interface was a habitual deterrent to stepping out of his comfort zone and learning the CLI. Temporarily restricting himself to use only CLI was a focusing mechanism to help him gain strength in a weak area. His efforts demonstrate the hacker ethic quite well. He could have easily stuck with the familiar, but decided to force himself to go out on a limb.