"how should Israel defend itself from Hamas/these kinds of attacks?" That's like asking: How should slave masters, colonizers or occupiers protect themselves from the resistance of their victims? Or, as Norman Finkelstein put it, "Do concentration camp guards have a right to self defense?" This is not to whitewash any atrocities that were committed by the oppressed in this case as they were attempting to resist their oppression. But unless you're going to condemn all historic slave rebellions--many of which were bloody--or the American Civil War--which left half a million dead, including many civilians--there is no moral consistency to your argument. The responsibility for ALL violence in a conflict rests with the oppressor, colonizer, occupier, slave master. Without the initial and ongoing oppression, there would be no victims who might be said to have resisted inappropriately.