A major goal in a propaganda war is to frame the issue on your terms. For example, in labour disputes, businesses (and their political and media allies) often claim the argument is not with the workers but with the "union bosses." The objective is to convince the public and perhaps even union members that management has no quarrel with their decent, hard-working employees, it's all the fault of the trouble-making union leaders. This is nonsense, of course. Unions are thoroughly democratic organizations and their leaders legitimately represent their members. But if management can successfully sell its message, and it often does, it can gain the upper hand in public opinion, an important advantage.
Israel, with its powerful publicity machine, aided and abetted by Western political and media elites, has been highly successful in just such a framing of its assault on Gaza. It has sold the issue as Israel vs Hamas, sending the message that Israel is not assaulting the good people of Gaza but rather just this terrorist organization called Hamas. The hundreds of Palestinians who die, and the thousands injured and driven from their homes are not the enemy, just unfortunate collateral damage, victims not of Israel but of Hamas.
But Hamas is in fact the democratically-elected government of Gaza. Khaled Mashal's Hamas is just as legitimate a representative of Gazans as Benjamin Netanyahu's Likud Party is of Israelis. Israel vs. Hamas makes no more sense than Likud vs. Gaza. The conflict should correctly be framed as either Israel vs. Gaza or Likud vs. Hamas. But by selling "Israel vs. Hamas," Israel has created the impression that Netanyahu truly represents his people whereas Hamas represents only its members, a bunch of terrorists, a highly useful lie in the propaganda wars, a lie completely swallowed by the Western media.
Israel not only has the biggest guns, it also has the best PR. The Palestinians get beat up on both fronts.