Earlier quoted context omitted.
There's nothing particularly great about nationalism, because "nation" itself is an abstract concept that's inherently malleable. And thus we get those nebulous "national interests" or "national security", which seemingly justifies everything if you can get people hysterical enough about it.
Any tribalism gradation is abstract. If we agree that humans naturally go for some sort of tribalism, then we can discuss which sort of tribalism is most efficient. Tribe-as-extended-family tribalism is brutal. Pan-* tribalism (as USA) seems to start splitting into smaller tribes because it's hard to find common ground for people living in wide variety of historically caused socio-economic conditions (e.g. rust belt…
What nation and nationalism brought to Europe is a series of wars that were as destructive as religious ones, at the time when religious fervor finally died down. And it is still doing more of that.