The massacres of civilians at Deir Yasin in 1948, Kibiya in 1953 and Kfar Kassem in 1956, for instance, really were just that, massacres. But such events were atypical and were met with horror in the wider community, while great efforts were subsequently made to prevent their recurrence. Indeed, the IDF has shown a consistent commitment to fight its battles justly, as dramatically demonstrated by Operation Defensive Shield in Jenin in 2002. Instead of bombing from the safety of the air, Israel lost 23 soldiers in hand-to-hand combat 'so that the Palestinian terrorists would be defeated with as few [Palestinian civilian] deaths as possible' (p. 255).
Israel's behavior during its assault on Jenin has often been hailed as a model of morality. Here are other examples:
I am proud that we were there, that we fought, and I also am proud of the morality of the battle. The camp was not bombed from the air in order to prevent innocent civilian casualties, and artillery was not used even though we knew about specific
areas in the [refugee] camp where terrorists were holing up.
--Dr. David Zangen, Seven Lies About Jenin, Ma'ariv, 8.11.2002
In Jenin, Israel's government decided to pursue a course that placed much greater risks on Israel's soldiers but that greatly reduced the dangers to Palestinian civilians. We announced over loudspeakers our intention to clear out the terrorist infrastructure in the camp and warned everyone to leave. Then, instead of bombing from the air or using tanks or heavy artillery, our soldiers were sent on a harrowing mission. They painstakingly went from house to house, moving through a hornet's nest of booby traps, bombs, and armed terrorists. After thirteen Israeli soldiers were killed during one mission, we still refused to use our air force or heavy artillery.
--Natan Sharansky, Jenin: Anniversary of a Battle
Not only was Jenin not a massacre or an unparalleled catastrophe but it is regarded by many as a model of how to conduct urban warfare against terrorists hiding among civilians. (...) Instead of bombing the terrorists' camp from the air, as the United States did in Afghanistan and as Russia did in Chechnya, with little risk to their own soldiers but much to civilians, Israeli infantrymen entered the camp, going house to house in search of terrorists and bomb-making equipment, which they found. Twenty-three Israeli soldiers and fifty-two Palestinians, many of whom were combatants, were killed.
--Alan Dershowitz, The Case for Israel, 2003, p. 144
In Jenin there was a battle - a battle in which many of our soldiers fell. The army fought from house to house, not by bombing from the air, in order to prevent, to the extent possible, civilian casualties.
--High Court of Justice of Israel
All of these pieces, as well as the hundreds of similar ones you will find on the Internet, argue that the Jenin operation was particularly moral because Israel did not bomb from the air but did house-to-house searches, thus minimizing civilian casualties.
But in December 2008-January 2009, Israel behaved quite differently during operation Cast Lead. In this war, Israel didn't risk a single soldier in hand-to-hand combat, but instead bombed all houses where terrorists were holed up, in addition to a large number of buildings that contained none. Jenin had been called not a massacre because the 500 casualties initially reported were later found to be just 52; but in Gaza, 1300 people died, including, by Israel's most ardent apologists' own estimate, at least 300 civilians.
You would think that would lead Zionists to lament the IDF's diminished moral standards. After all, in Jenin they declared that the IDF's virtue had been not to bomb from the air, and the Gaza op was completely carried out from the air. They should have observed that, while the IDF is and will always be the most moral army in the world, unfortunately it's not as moral as it used to be.
But somehow they haven't made that observation. The discourse has changed, and now an operation is moral not if the attacking army refrains from leveling buildings with its air force; it's moral if, in addition to the bombs, the warplanes drop leaflets calling on civilians to evacuate the area.