
But I think what makes ethnonationalism particularly problematic in the case of Israel was the dynamic of new people moving in, with the goal of creating a majority over the already present inhabitants. There is a subtle difference in how the other ethnic groups will react to “we are in a state that is mostly another ethnicity” and “another ethnicity is moving here to make a state for themselves”
Correct. Palestine (as it was called after the Bar Kokhba Revolt) has had a notable Mizrahi and Sephardic population for millennia. But Palestinian Jews were a pretty small population relative to the quantity of Zionist settlers who arrived later. And even the pre-state Zionists of the first, second, and third Aliyahs were dwarfed by the quantity of people arriving during the holocaust and after the founding of the stage of Israel.
Sometimes settler colonialism occurs in a form where you have an existing non-colonizer population of an ethnicity, whose numbers are then increased by a large number of co-ethnic colonizers. Good examples are Turks in Cyprus, English in Ireland, Italians in the Dodecanese and Dalmatia, and Germans in much of Eastern Europe.