I have been describing both. You continue to misunderstand that the number of lives does not matter for ****. Period. It could be one Israeli life for zero Palestinian lives, and the calculus would be the same. It could be one Israeli wounded for a thousand Palestinian lives, and the calculus would be the same.
A government must protect its people. This does not mean that a government must endeavor to prevent as many casualties as possible, this means that a government is duty-bound by the terms of the social contract (more on that later) to come to the defense of its citizens. A government that does not defend its population is not living up to those terms.
The social contract is an implicit agreement individuals made in order to form a society. Society cannot exist without the social contract. Society, and by extension the government that embodies that society's direction, must abide by those terms.
The terms in particular fluctuate as much on a geographical basis as on a cultural one (please do not confuse culture with society). There are some, however, that are fairly immutable. The first is that the individuals that form this society must give up certain freedoms and liberties that do not lend themselves to cooperation and beneficial action. Indiscriminate killing, theft, rape. You probably get the point.
In exchange for the relinquishment of those freedoms and/or liberties, individuals in a society also abdicate their responsibility to defend themselves from outside threat. I will repeat this for emphasis. Members of a society are not expected to defend themselves from external threat.
I want to be quick to point out that this doesn't always happen. When a government fails to defend its population, it is in breach of the social contract. It has, at the very basest level, failed in its most important objective.
This is why, ethically and morally speaking, it is reprehensible and irresponsible for Israel to not retaliate when Hamas launches attacks that are explicitly intended to kill or wound its population.
Battuta explains it best with his apartment metaphor, which I will re-appropriate. The members of an apartment complex, upon moving in, are not responsible for the security of the facility in any except the most basic terms (keep your doors locked when you're away). It is the responsibility of the land lord and/or management of the facility to ensure a safe environment for the tenants to live in. In the event of a threat, the management must respond or lose all credibility as to providing a safe environment. If the management cannot guarantee safety, the tenants will move, and the complex will fail. Such as it is with society and its government management.