Civilians in Gaza do not fit the definition of hostages,
preventing Gazans from returning to their ruined homes under threat of death in exchange for something is textbook definition of being held hostage.
A hostage is a person seized by an abductor in order to compel another party, one which places a high value on the liberty, well-being and safety of the person seized—such as a relative, employer, law enforcement, or government—to act, or refrain from acting, in a certain way, often under threat of serious physical harm or death to the hostage(s) after expiration of an ultimatum. The Encyclopædia Britannica Eleventh Edition defines a hostage as "a person who is handed over by one of two belligerent parties to the other or seized as security for the carrying out of an agreement, or as a preventive measure against certain acts of war."[1]