From the Manichaean view, the issue as to whether Mr. Breivik is “sane” or not is a non-issue. The real issue is whether a person who could commit such as as Mr Breivik did is “evil” or not. The answer to this question was validated when he killed 77 people in Norway.
Motives for an atrocity do not mitigate the tragedy of the atrocity. Mr. Breivik admitted to harboring what any decent society would clearly view as monstrous thoughts and acted on them.
Until society can wake up to the reality of evil and that it is present in the world, then similar cases will continue to happen and mankind will continue to look in the wrong spot for the answer: “How could such a terrible thing happen?”
Answer: Evil exists. It is real and it is among us. One need only look at the face of such persons as this criminal in Norway and you will know it is present in this world.