Tying that back to the subject at hand - forming a nation-state around the contours of a people in order to effectuate the autonomy and self-determination of that people, as well as to protect them against the all-too-common depredations that are inflicted on the minority members of a community by the majority (in any political structure whether nation-state or no), is not an illegitimate political project. It's not artificial, or imaginary, or whatever other imprecation you want to label it as.

Being more specific, in Israel they had that for a brief time. But Israeli "settlers" would move across borders and take land (often by force), and the Palestinians voted in an organization whose stated goal was to drive Israel into the sea. Both were nation-states drawn around people of common heritage and community. But both have what appear to be irreconcilable goals. In situations like that, someone is going to win, and someone is going to lose.

I'm sure part of this is ancestral claims to land. But I think another factor, or perhaps a "force multiplier", is that one particular area is important to multiple peoples. And entirely for make-believe (i.e. religious) reasons. Jerusalem and the Temple Mount. Each "side" views the others' presence there as a blasphemy.