Hamas's tactics are no different from the Viet Cong's (attacking villages, taking hostages, using tunnels and guerilla warfare etc) and their goals are the same (reunifying their nation and driving out colonizers). These are simply the most effective tactics for driving out occupiers, and they wouldn't be necessary if the colony wasn't there in the first place; decolonization has always been violent, and will continue to be so until the colonies are removed.