The Israeli's hit their target and took him out. The others were "collateral damage". The target was a combatant. When Hamas sends their fodder out to blow themselves up, the children frequently ARE the targets... That's the major distinction...
This same distinction is something that you seem to blur with our actions in Afghanistan as well. By definition, you can't have "collateral damage" if your target is noncombatants (see the World Trade Center)... You can in Afghanistan when bombs miss their targets (their targets being combatants).