To be clear, I don't think including or excluding the blue part changes much.
You're watching your country commit a series of atrocities against civilians. What Hamas did in October is evil. What Israel has done since is evil. I understand that there will be people who can't live with this and will choose to justify it in order the avoid the cognitive dissonance. For you, this is telling yourself that the alternative is much greater harm would result, Israel faces an existential threat and must have secure borders.
I'm from the UK, and witnessed the same behaviour before, during and after the invasions of Afghanistand and Iraq. We had to do what we did. Otherwise we would be under severe threat.
The truth is that choices were made to do evil that were not self-defence. Just like these bombs that are killing babies, destroying homes, schools, hospitals and refugee camps are not securing Israel's border.
Again, I can understand why you might tell yourself this, though.