Breivk's MO was "international terror" and it has been years since an indiginous terrorist committed acts in his own country, excepting Northern Ireland sadly.
So the "Al-Qeida" angle was perfectly logical for that point of view, I remember little "crowing" at the time, though there was an attitude of "well, another one."
The reaction to the French shooting was "Look, this is what happens when politicians get Xenophobic, Sarkozy is responsible for his recent rhetoric". Certainly, the Guardian here ran pieces to that effect and and I have no doubt the French left-leaning press were even more forthright. The fact is though, they were wrong and Sarko looks right.
Brievik is shown to be an anomoly, an aboration, and the reasuring narrative of fear is restored.
To be fair to both sides, the MO was more IRA to Red Terror than Jihadist, but it was always more likely to be a Muslim overall and the fact that the Left jumped the gun serves them right.