Terrorists are by definition extremists. They want to upset the status quo to force people to take sides and create a situation where they feel they, who are righteous, have a better chance of being successful or at least relevant. Whether that is a race war, holy war or revolution. The killing itself isn't particularly relevant until your fighting over land and then normally in form of ethnic cleansing.
The analysis you linked misses a the point of e.g. the terrorist plot in Norway. It's wasn't just about killing people, he deliberately tried to effect politics by killing a generation of people he disagreed with. He also believed that it was part of and going to lead to a larger conflict.