Whoever commits terrorist acts, should be neutralized. It does not matter if it is 10 or 100,000. Terrorists, need to go.
It is however not acceptable to kill civilians. Even 1. But unfortunately in these kinds of conflicts there is always huge collateral damages.
Your solutions to avoid this collateral damage and getting rid of apartheid, racism etc are not practical solutions while there is a terrorist group colluding with other nations and acting against Israel (and against Palestinians themselves).
PS: Israel's ambassador was not saying 600K in Gaza. She was talking about Nazi Germany and the civilian deaths there as a comparison to say that the collateral damage is inevitable but worth it.