I'm sure people are sick of me getting all nit-picky and stuff, but there's a difference between a lone madman killing people for ideological reasons, knowing full well he or she'll be caught, imprisoned, and never able to repeat the crime, and someone who is part of a group who does or organizes the same thing, where even if some members of group end up being caught, others will be able to take over and continue the rampage.
"Terrorism" does not mean "Anything bad I disagree with", it means attempting to promote an end using, well, terror, and a single, one-off, act really isn't promoting terror. "Terrorism" is a bad word - ie a word that means an act that's despicable - and what happened in Oslo was utterly evil, but just because it's a bad word doesn't mean it's appropriate.
We don't, for example, call Al Qaeda "child molesters". We don't say the IRA and UDF were engaged in "genocide". We don't call the Shining Path guerrillas "serial killers".
Terrorism is the word of the day, and it shouldn't be. It's been used to describe everything from the Oslo attacks to the activities of Wikileaks. Every time it is misused it devalues the word, its value, and its usefulness.
None of which should change the fact that those who have been whipping up fear and hatred against Muslims and against those who preach tolerance should be utterly ashamed of themselves.