Take any organization, founded for whatever reason, and pretty soon its first order of business becomes self-preservation.
Back in the Middle Ages, when the Catholic Church needed money, the Pope sold indulgences whereby wealthy mortals could assure their souls a shortcut past Purgatory and straight through the Pearly Gates.
When Jonas Salk discovered the polio vaccine, the March of Dimes reinvented itself as a crusader for pre- and neonatal care.
So now comes Hamas, whose popularity with Gazans is in decline because it is failing to deliver on all those mundane promises about lowering crime, keeping the lights on, and getting the garbage picked up. A dingy light bulb clicks on over some strategist's head, and he says, "I know, let's go shoot rockets at the Israelis! They'll retaliate in force, as they always do. We hide amongst our own people, they get mowed down, we fight back in their name, and even though we're sure to lose, we're heroes! We sweep the next elections!"
That's all well and good, except for the people who got mowed down. Nobody asked them.