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.
<...> your country had the means to stop it from happening again, would they?
By killing more civilians? Oh yes, that will definitely make sure it will never happen again. That might work in fiction, but in real life, it just guarantees more violence in the future.
Even if it meant other likely innocent people would die in the process as well?
That's a war crime. If the country is willing to do that, they should be willing to accept the punishment for it.
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?
Has the history not taught you anything? Peaceful Palestinians who had nothing to do with Hamas, who had their entire families slathered, are NOW more likely to blame Israel for their crimes and join the Hamas (or someone new) in retaliation. Israel is the obstacle to peace, not the other way around. Ignorant people like you who justify civilian killings are the reason monsters like Netanyahu are in power in the first place. His own people don't like him and want him to step down, since when he was offered to bring the hostages in December, February, and April he refused. He needs this war to go forever, since the minute it ends he's done himself.
Would you have a problem with dropping a bomb on a school in your city if people there were taken hostage by some terrorists? By Israel's actions, that would be justified killing.
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.
Most people don't an issue with targeting people responsible for civilian deaths. Hamas and IDF are militants, and Israel has absolute right to attack them in the name of "self-defense" or even simple vengeance. On the other hand, dropping bombs on schools, hospitals, religious buildings or residential buildings where civilians are is a war crime.
Your question without all the rhetoric is: Does self defence justify elimination of an entire nation, country, ethnicity or people?
The simple answer is no. Elimination of a nation, country, people or ethnicity is the textbook definition of genocide.
If you read the article, you would know that ICC is charging hamas for war crimes as well as the Israeli regime, because war crimes by one party do not justify war crimes by the other party. So you do not need to think where the line should be drawn. The line already exists and Israeli regime has crossed it.
Except Palestine isn't a country, and Israel had already killed more Palestinians over the course of the year before Oct 7 happened. Gaza is an occupied territory, and you shouldn't be surprised if an occupied people decided to kill occupiers (most of which were actually active IDF personnel).
And then there's the question of the response. With the benefit of hindsight, how would you rate the US response to 9/11? Did the actual response make the US safer? Was killing and maiming millions of completely uninvolved people in 20 years of war worth it?
My country was invaded by terrorists on September 11th, 2001, killing nearly 3,000 people. We waged war on the entire region the terrorists came from, eventually killing the leader of the group, and nothing changed. All our bombing did nothing, all our sacrifices of innocent people were for naught.
Amazingly, killing a bunch of people who had nothing to do with the terrorists that attacked your country is a bad move, and only serves to create more terrorists as people watch their loved ones die by your hand and grow to hate you.
If your takeaway from America's terrible actions post-9/11 is that we should've been even more brutal and wiped out the entire mostly-innocent population of the middle east, you've got the wrong takeaway.