Hamas bombing Israel with rockets is responsible for the death of Arabs in Gaza, as much as Nazis are responsible for the German victims of war that Nazis started.  

Fighting Hamas indeed was an act of self defence by Israel, who did exactly, or less, than any other country would do when bombed by another entity.

Arab states got 99.99% of the Middle East lands from the Ottoman Empire, and have no rights to claim even more when they refuse to give anything to Druze, Kurds, Bahai, Azeris and other minorities living among them.