[rayiner]

The partition plan wouldn’t have expelled anyone from their homes. Most of the land that became Israel belonged to the Ottoman Empire itself. Part of it was purchased by Jews over decades. Arabs weren’t to be expelled from the remainder, they would just become part of the new Jewish state. And, of course, it never would’ve affected Arabs in Syria, Jordan, etc.

[Georgelemental]

> purchased by Jews

Many of these purchases were from wealthy Ottoman landowners who had in many cases never seen the land they owned. The peasant families that actually lived on the land for generations had no say in the matter. I'm not faulting the purchasers for conducting legal business transactions, if anything the fault belongs to the feudal system of the Ottoman Empire—but none of that matters to someone who has suddenly lost their home and livelihood.

> Arabs weren’t to be expelled from the remainder

I don't think the historical record bears that out. Why did Israel not let the civilians it displaced return once the war ended, if the displacements were merely a temporary military necessity? And certainly massacres like Deir Yassin were not military necessities, though they did scare many Palestinians into fleeing.

[rayiner]

You’re mixing up two different things.

The question we were talking about above is: What caused the Arabs to attack Israel the day after the UN Declaration? Note: it was not just Arabs in Mandatory Palestine, it was Arabs in Egypt, Syria, Transjordan, and Iraq. All of them attacked Israel. Why? It wasn’t Arabs in Palestine being forced to leave their land. That wasn’t part of the partition plan, and hadn’t happened yet. The Israeli Declaration of Independence specifically asks Arabs to stay and become equal citizens.

As to why Israel hasn’t allowed Arabs who fled to return, I suspect it’s because the Arab countries tried to kill Israel in its crib, and then expelled a million Jews from their own lands.

[Georgelemental]

> That wasn’t part of the partition plan, and hadn’t happened yet.

I must admit I don't know as much as I would like about this, so please correct me if I say something stupid (and share reading recommendations), but: my understanding is, "Israel" at this point was composed of several factions who disagreed greatly about methods. Probably Ben-Gurion did not have ethnic cleansing in mind, but Irgun and Lehi did, which was enough—the most radical factions were also most willing to fight, which gave them outsize power. (Though even Ben-Gurion did not intend to stay only within the borders allotted by the UN, he intended to take control of even Jewish settlements outside the partition borders.)

As for the war: the invasion by the Arab countries upon Israel's declaration of independence was an expansion of a civil war within Palestine that had already been going on for more than 5 months, and that the Palestinians were decisively losing. The Arab states hoped mostly to save face and to stop the flood of Palestinian refugees that would result if the current trajectory continued.