If your country was suddenly invaded and had 1200 mostly civilian, including women and children gunned down in one of your cities, including shooting up a concert, and your country had the means to stop it from happening again, would they? Even if it meant other likely innocent people would die in the process as well? Would your country be willing to wipe another country off the map in order to make sure that your people were never attacked and killed again?

So that’s the reason. Isreal was attacked with no regard by a country that ran by a group of people after the goal of completely eliminating Isreals existence.

Now the entire middle easts history is convoluted as hell and many sides have fought with many others. The “blame game” puck could be passed around 100 times. But what would you feel your country would be justified to do if they were invaded by surprise like that? Would they make sure it couldn’t happen again? Would you feel it was justified? It may not be a clear yes or no answer, or where a line should be drawn.

Holy strawman gish gallop, Batman!

The author of the article effectively refutes all of your novel of deflection with one sentence:

The proposed charges are not about whether Israel can defend itself but how, that is, not by committing war crimes.

Later on, he encapsulates the very thing that all of civilized society is based on:

regardless of the perceived justness of one’s cause, it never justifies war crimes.

Never. Under any circumstances. Ever.