This is a very good question.

My understanding is that the colossal tradegy of Holocaust made Jews realise that not fighting back is an existential threat for them.

When Israel was established then Arabs did not accept its existence nor the existence of Jews in the region. What followed was a genocidal war to exterminate Jews in Palestine and destroy Israel. We know this war today as Israel war of independence.

The Arabs who participated against Jews in this war fleed in fear of retribution and were not allowed by Israel to return. We know these people and their descendants today as Palestinian refugees (they have special inheritable status given by UN).

After the war Israel was established nearly within the borders of UN assigned Jewish territories and UN assigned Arab territories were annexed by Egypt (Gaza) and Jordan (West Bank). But it was still not tolerable for the Arabs who again in 1967 attempted to exterminate Jewish state with the war.

After the failure Isreal took control over larger territory that was then inhabited largely by Palestinian refugees (Palestinians) - West Bank and Gaza and also part of Egypt over the Suez canal and part of Syria called Golan Heights. The reasons where twofold. First the UN assigned territory was clearly not realistically defendable and second the large part of the previously not controlled territories like Bethlehem or Jerusalem were believed to be Jewish lands (historically Jewish lands were between Jordan River and Mediterranean Sea). Territories belonging to Egypt were later returned by bilateral treatis (but Israel kept control over Gaza).

Fast forward to today and it appears that Palestinians have not abolished the idea of genocide against Jews. It has been clearly established that the 7th October attack was a genocidal act to eliminate as many Jews as possible. Around 3000 Palestinian men took part in it, Hamas had around 40000 fighters. This demonstrates that they had wide support among Palestinians.

This leads us back to Holocaust. Jews promised to themselves that they will not let the genocide happen against themselves ever again. Yet it happened.

What is going on in Gaza is a systematic work to eliminate this threat.

They do this with minimal risk to their soldiers who are mainly reservist e.g. common people with military training. They can't afford to lose thousands of people. Palestinians in contrast value martyrdom and are willing to take very high risks (like attacking an armored vehicle with a RGP within a group of civilians next to the hospital entrance (this has been documented by the video evidence)).

It is not a police operation. It is a military operation against heavily armed and trained opponent. The weapons are chosen accordingly. The urban landscape makes it especially difficult and destructive. Regardless as far I have observed then Jewish military has made great efforts to systemically minimise civilian casualties.

What they did not realise first was that in addition to the military operation on the ground there is also sizeable information war against them and when the enemy can find many willing sympathisers then the enemy can produce what ever claims they please regardless of the truth as was demonstrated by the al-Ahli Arab Hospital explosion.

I haven't observed the situation closely for months but by then Jewish armed forces evolved to be more open in their communication and to communicate more clearly the threats they had to fight against.