These sorts of parallels never work perfectly. But we can try the thought experiment.
I think Ireland pre-independence is probably the closest we can get.
The land was ruled by another power (Britain). Most Irish had left, either because of poor conditions or oppression, and now constituted a big diaspora population. So far, the parallel holds.
Imagine, in, say 1900, a horrific pogrom by Protestant extremists in North America of Irish-descent Catholics, which had killed over half of the world’s population of Irish people, many many millions over a few years. Let’s say the same had happened to a lesser degree across Europe too, and that many European rulers agreed with the pogromists.
There might have been a movement that said: we Irish aren’t safe except in our own homeland. That homeland should be Ireland, which should be freed of British control and become independent. We Irish will go there to escape persecution and build a country.
If Britain, with UN endorsement, had left the land and created an Irish state, partitioning the land, for two communities.
Should that Irish state have been tolerated?
If the northern Irish Protestants had joined with surrounding European states to invade and destroy the new Republic of Ireland, would that have been justified?
If that attack had failed and Ireland continued to exist, as an Irish state, what should we feel about it and them now?