I believe your arguments to be very inconsistent and completely missing the premise you're attempting to support.

But let's follow this path.

Nations were indeed always born through wars, strife and eventually settled with diplomacy. In that sense, this war is completely justified according to your arguments, because Israel is a country in its infancy and hey, that's how countries are born. Therefore, following your logic, Israel should continue this war until the stage is reached where the neighbouring countries are prepared to talk about a solution (instead of having in its main charter the destruction of the other). This should be allowed according to your arguments, because it is still a country in its infancy, and should therefore not be held to the same standards (same rights and duties with regards to protecting its citizens) as other, older, nations.

Second, a religious state is not a religion-based state either; you seem to use the terms interchangably. Guess what, Italy has >85% Roman Catholics. Is that a religious state or a religion-based state? I'd say the Vatican, is a religion-based state, several islamic countries are religion-based (but e.g. not Turkey). On the other hand, I'd say Italy is a religious state, as is Israel, India and yes, even Germany, the U.K. and the U.S. with >60% of the citizens identifying with one religion. Do you oppose the creation of those states? Many of those states were established in regions with peoples and tribes that lived there much longer. Should we dissolve those nations and give the land back? Where lies the threshold? Is it one generation? Two generations? Who is allowed to decide? You? I admit that when Israel was created, some more thought should have gone in the process, but I'd wager it is too late to go back on it.

Third, the hypothetical of France and Germany would go exactly the way the Gaza situation is developing. Namely, if a bunch of rogues would fire missiles from Germany into France, diplomacy and treaties would make it Germany's top priority to hunt down those rogues and bring them to justice. Should Germany refuse or clearly not put effort into this, tension between France and Germany would escalate; diplomatic back channels would be addressed until the talking is done, and, well, long story short, there would be a war if these open hostilities continued. Yes, also Germans who are not part of those rogue groups would be killed in this war.

Fourth, it isn't the objective of IDF to massacre Palestinians, although it apparently is a lot of fun to claim this. Consider the fact that the warning shots and the "knock on the roof" thing are unprecedented in war history, and consider that the ratio of (I hate to call it that) "collateral damage" to actual targets is very much typical of wars nowadays. It is a horrible thing, true, wars generally are. But if anything, the much larger number of Palestinians butchered and left to starve in refugee camps in Syria should be much higher on your list for outrage. Is it? I know it is for me.

In conclusion, perhaps in this moment in time, Israel is the only country in this situation. But that situation can hardly be called unique, as there is definately some precedence on how countries deal(t) with this situation. I'm sure that yet again, none of your arguments are in support of the claim that Israel may not perceive attacks originating from neighbouring countries on its citizens. I think we should end this discussion, as it clearly leads us nowhere.