The bombing in the land of Quisling looks like an elaborate diversion designed to provide cover for the real operation, which was to murder as many members as possible of the youth arm of the left-wing, anti-Israel Norwegian Labor Party, being groomed at their summer camp for future service:
The Workers' Youth League (Bokmål: Arbeidernes Ungdomsfylking, Nynorsk: Arbeidaranes Ungdomsfylking, or AUF) is the youth organization affiliated with the Norwegian Labour Party.
AUF was formed in April 1927, following the merger of Left Communist Youth League and Socialist Youth League of Norway. It's [sic] ideology is social democracy and democratic socialism. The current leader is Eskil Pedersen. Many former leading figures in AUF have gone on to serve in significant positions in government, such as the incumbent Prime Minister of Norway, Jens Stoltenberg.
A survivor of the shooting explains what all those kids were doing on that island where the murders occurred:
What can I say? The last normal thought in my head was about the AUF´s organization of students. I had just been to a political workshop (that´s what we do at Utøya) – and was on my way up tp [sic] the AUF-shop where I was going to take a shift. ...
Blowing up important buildings in Oslo and killing the future politicians of the Arbeider-party (ed. AP) who are attending summercamp at Utøya. What wrong have we done?
Those who resort to violence have run out of arguments. How could he do this to my AUF-friends? It seems so surrealistic. I don´t understand. I can´t comprehend.
She doesn't understand because she has been taught not to. This formal, political indoctrination of the young is designed to pave the way for the strident, anti-Semitic views of the Norwegian Labor Party, as detailed here, here, here, here and here. Which goes far to explain what could possibly motivate an extremist fanatic of the opposite persuasion, equally misguided, in this case a loner with delusions of grandeur.
[A] young man is not a proper hearer of lectures on political science; for he is inexperienced in the actions that occur in life, but its discussions start from these and are about these; and, further, since he tends to follow his passions, his study will be vain and unprofitable, because the end aimed at is not knowledge but action. And it makes no difference whether he is young in years or youthful in character; the defect does not depend on time, but on his living, and pursuing each successive object, as passion directs. For to such persons, as to the incontinent, knowledge brings no profit; but to those who desire and act in accordance with a rational principle knowledge about such matters will be of great benefit.
-- Aristotle, Nicomachean Ethics 1.3, here
[A] young man is not a proper hearer of lectures on political science; for he is inexperienced in the actions that occur in life, but its discussions start from these and are about these; and, further, since he tends to follow his passions, his study will be vain and unprofitable, because the end aimed at is not knowledge but action. And it makes no difference whether he is young in years or youthful in character; the defect does not depend on time, but on his living, and pursuing each successive object, as passion directs. For to such persons, as to the incontinent, knowledge brings no profit; but to those who desire and act in accordance with a rational principle knowledge about such matters will be of great benefit.
-- Aristotle, Nicomachean Ethics 1.3, here
