This is true so long as that self-defense includes every measure possible to make certain that there are as few enemy civilian casualties as possible.
That sounds reasonable until one considers the fact that Israel already does more than any other country on earth, if not any other country in all of human history, to decrease enemy civilian casualties during points of conflict.
Really what Israel is being told by western leaders, and most of the western-left, more generally, is that legitimate use of Israeli self-defense is contingent upon Israel not using its capacity for self-defense. In other words, Israel may defend itself so long as it does not defend itself. If it insists upon defending itself, through actual measures of self-defense, than that self-defense is entirely illegitimate because it results in unnecessary and unacceptable deaths within the opposite civilian population.
In this way the western-left promotes Hamas' media agenda which is to get as many civilians killed as possible so that they can then whine to the media about Jewish-Israeli barbarism.
It is fairly amazing how much death and destruction that Hamas is willing to bring down on the heads of Gazans merely for the purpose of giving Israel a PR headache.
Meanwhile, as western-leftists hold the Arab-Muslim world to no standards of human decency, whatsoever, they hold the Jews of the Middle East to what Matt and Zach over at Huffington Post Monitor dubbed the "ethereal standard."
Writing in 2010 with Operation Cast Lead freshly in mind, the brothers argue:
This is not a case of double standards, in my view. It is instead a case of the ethereal standard. The HPers won't tell you what exactly Israel should do when confronted with enemies like those they have. But what they do know is that Israel is doing the wrong thing. There is a standard for how Israel should behave in their minds, but Israel by it's very nature will never meet it. The standard will continue to climb higher and higher so that it is forever out of reach.It's deja vu all over again.
Cast Lead and it's fallout was the perfect example of this. The anti-Zionists had no answer to how to stop Hamas' rocket fire, but they were 100% sure that Israel went too far. They had no response for Colonel Richard Kemp's claim that Israel was doing more to avoid civilian casualties than any other army. They instead just said that "Israel killed too many people," and it doesn't matter what other nations do. They then went on with their rants. For Israel one civilian casualty is too many. Other armies fighting in other wars never even enter the conversation.