It makes me uncomfortable to think about, as it can easily be corrupted towards much more nefarious ends than that of people sticking to like people. And it's not something really reliable across humanity as a whole. It does seem to work fairly well for populations that adopt a largely cohesive Christian faith on top of their ethnic background, but outside of that, not so much. If ethnonatuonalism worked by itself, you would have much less warfare abd societal strife in areas that were primarily controlled by atheist, Islamic, and Bhuddist regimes.

So, it needs to be tempered by something that prevents tribalism and othering.