He writes that he has no faith but he values the cultural aspect. It's part of the norwegian cultural heritage which he so dearly want to defend. The Knights Templar is probably something he's picked up from the english European Defence League btw.
I still think he's nothing more complicated than a man went downhill ever since 2008. His manifesto is full of excuses, like his World of Warcraft playing. He went bankrupt the period he did hardcore raiding for instance. Maybe he set too high expectations for himself. He tried to re-establish himself as a publisher for conservative causes, but failed. During all this he maybe brainwashed himself on writings of islamification and conjured up this last nobel act to make his mark.