It's always funny when people act like they know about a subject, and then argue against things that have long been settled. Acquiring territory through war has been illegal since before Israel existed as a modern country.

It was recognized as a principle of international law that gradually deteriorated in significance until its proscription in the aftermath of World War II following the concept of crimes against peace introduced in the Nuremberg Principles.

https://en.wikipedia.org/wiki/Right_of_conquest

It doesn't matter what "historically worked". Weapons in the past 100 years are too powerful to allow for conquest. Israel's occupation of Gaza, the West Bank, and East Jerusalem violate international norms and the international community doesn't recognize occupation as justified.

And they can't just keep the land because they were attacked first. Only defensive wars are permitted under international law.