let's keep it simple and call him "crazy."
Glenn Beck, Sarah Palin, right-wing religious fanatics, and the Tea Party appear to be responsible for a nut-case in Oslo to plant bombs and go on a shooting spree. Now I understand that words like "crazy" and "nut-case" are likely to drive the community of licensed psych-type people up a wall, but they're perfectly adequate to describe this guy.
Listening to pundits proclaim all the possible triggers, influences, and past life history as being the "reason" this man was driven to commit unspeakable crimes is ludicrous. If this were the case, we would have events like this taking place multiple times per day, every day. If the mere reading of certain material was a trigger to antisocial behavior, then why in heaven's name would any parent allow their children to read Harry Potter? Take a trip to any comment section on the Huffington Post and witness some real verbal violence. How many of those people are running around blasting away anything except their big mouths?
I understand the need for humans to make sense of the senseless. It makes us feel better to have an explanation. Until the next big news item pushes this geek off the front pages, there will be articles ad nauseum about the possible reasons. Each new article will make the claim of having the only correct answer to the age old of question of "why."
Let's keep this simple. Anders Behring Breivik is batshit crazy. I don't care how he got that way because it's impossible to know because, you see, he's batshit crazy. It's impossible to understand batshit crazy so why bother. Lock him up for the rest of his life and let's move on.