It is not only Settler Colonialism
Good point, Dan. But Zionism is vastly more insane and indefensible than other varieties of irredentism, so much so that it really doesn’t fit the word. Every example of irredentism I know of involves nations with some kind of ethno/linguistic basis seeking to reclaim territory currently occupied partly or predominantly by people of that ethnicity. And the territory they seek to reclaim is right there on their border. These claims tend to be relatively reasonable.
Zionism demanded far-away territory across the seas that was not occupied by the ethnicity in question, and based that claim on 2000-year-old tribal mythology. It’s as if I organized American celts and invaded and ethnically cleansed much of Western Europe to create a “celtic state"…except that would be more reasonable than Zionism, since it hasn’t quite been 2000 years.