there have been over 7,000 kassam fired on israeli territory since all jews were removed from gaza. israel responds by targeted killing of the rocket operatives. the rocket operatives use "human camouflage" as a deterrent against israeli reprisals. the effectiveness of that tactic is evidenced by the condemnation of israel over the infant's death. but under geneva convention rules of warfare:

"The Fourth Geneva Convention goes into great and elaborate detail about how to assign fault when military activities take place in civilian areas... Hamas is at war with Israel. But instead of separating themselves from the general population in military camps and wearing uniforms, as required by international law, Hamas members and other Palestinian terrorists try to use civilians -- the "protected persons" mentioned in [The Fourth Geneva Convention] 3:1:28 -- as living camouflage. To prevent such a thing from happening, international law explicitly gives Israel the right to conduct military operations against military targets under these circumstances."

Article 28
The presence of a protected person may not be used to render certain points or areas immune from military operations.

Geneva Convention relative to the Protection of Civilian Persons in Time of War

thus when the rocket operative fires a kassam at israeli civilians he/she cannot seeks th protection of civilian sandbags.