Everyone gets hooked on to SOMETHING that binds them through generations of active involvement ingrained in their genes or something internalized through:- imitation or interest or impulse or intellectual analysis or instantaneous emotional appeal or that creates some innate connection etc.
That SOMETHING could be any sort of affinity for or fervent and fond fixation avidly pursued which may lead to some identity.
That SOMETHING could be some art, belief, culture, cult, doctrine, dogma, faith, idea, personality, religion, political ideology, sports, music, science, technology, thirst for knowledge, keenness to understand life in depth through some search, helping others in multiple ways, making money, accumulating wealth, involvement in a profession or job, devotion, love of one's family or one's nation etc.
Therefore, everyone is at liberty to choose and claim affinity for any one or some of these SOMETHINGS.
So, those who find fault with a national identity manifesting as nationalism, would they be willing to give up their affinity for money, family, profession or their religious beliefs and practices.
However, the manifestation of one's fond affinity must not generate hate towards that of another or injure others or cause damage to the environment.
So, the ways of expressing or exhibiting one's fondness for a particular SOMETHING must not be too violent or exhibit any extremism.