I think the broader point was why look to the festival runners? Had the festival occurred at planned site one, it could well have been ambushed just as if not more easily. Possibly a more apt 'question' could have been, 'why focus on butchering a load of youths dancing to some music?', if there's a grievance with the militaristic tendencies and oppression of a certain regime, hammer the ones in uniform doling out the violence by order.
My problem with the hamas method of a load of rockets sent from palestine, they knew exactly what the reply would be so to come the soft flannel of isn't the reprisal terrible (although it is) rings rather hollow. It's blood for blood over generations. There is no healing.