An isolationist, he wants Norway to be Norway. Norwegian people, values, culture not some muddled, middling, multicultural Marxist and Islamic state which he sees the EU becoming.
He finds Marxism has crowded out national identity in education and the press with opposition belittled, dismissed or attacked. He finds high risk in a Marxist-led European Union believing it would follow other failed states before it like the Soviet Union in killing millions or follow the bloodshed that has come with prior invasions from Islamic radicals over the centuries.
Along with the Marxists, he takes issue with the Nazis and pre-enlightenment Christendom as blood-shedding imperialists.
This isn't about ideology or racial supremacy but national identity.
Even after the video, I can't see the connection between the attacks and his goals. How are they a means to further his cause rather than cutting the legs out from under it and playing into the very Marxist propagandist hands he fears.
He believes he just started the clock on the 70 year revolution. He thinks this will inspire more attacks, an underground, a movement. He plans on becoming the leader of a political movement from prison.
My reading so far is that he's given up on the political system as a rigged game and concluded that violence was the "only logical option" (his words) at this point.