Your definition of 'national' bespeaks historical amnesia. 'National' usually means the overcoming of the obstacles of geography, racial differences, historical differences and so on, to form a union. Yugoslavia was a nation; it has splintered into ethnicities.
The countries of Europe were not mono-racial. There are many different kinds of Germans; the French comprise Gallic predecessors, germanic Franks, and other western Germans; the English comprise French Normans, Danish, Anglo-Saxons, Britons and others; the UK of course is even more diverse; Italy is such a diverse mix of peoples that at one time the definition of 'Italian' was viewed as nothing more than a convenient construction.
Nationalism cements diverse groups into one.