We worry a lot about the I-concept of the individual, but rarely about the I-concept of the group. Families also sometimes have developed protuberant egos. And as for nations ...
Nationalism is a manifestation of the ego of a group, often exacerbated to an extent that social conditions deny to the individual.
Even associations, clubs, and particularly political parties, develop an I-concept with the lamentable and ridiculous results that accompany all manifestations of this concept.
Yet there is no reality in such phenomena, other than the ultimate reality without which phenomena could not manifest.
But just as there have always been families which have escaped the development of such a concept, and associations, clubs, even parties which are merely SUCH, so nationalism is only a sporadic growth and has not always existed in our or any other civilisation.
Many people are proud of this manifestation and regard it as a virtue, just as some people cherish pride as a virtue: les primaires civilisés, les civilisés primaires.
Perhaps if we are able to transcend the ego-ism of the group we may the more easily find the way to transcend the ego-ism of the individual, for one and all are identical concepts and, one and all, devoid of reality.