It’s eminently understandable why, with coverage of the terror attacks that killed 77 people dominating TV news at the time, Comedy Central executives in 2011 decided that reruns of the Futurama episode didn’t need to include the implication of the Prime Minister of Norway’s dismemberment when the terrorist who perpetrated the attacks targeted the actual Prime Minister with a car bomb

It makes sense at the time and that is the lense you need to look at the problem through. Depending on how close the air date of the rerun was to the attack I don't blame them as people may see it in poor taste despite the joke being there before the attack.

No doubt after the 11th sep or the London tube bombarding if a show rerun aired making light of those events an uproar could happen.