Some people did. As an example, my grandfather had to fight for the right to live according to his culture, because our country was invaded. Once you fought for your freedom, you begin to feel rather strongly about "nationality", defined as belonging to a group of people that share your cultural beliefs. And yes, you could say he "earned" his nationality. He did not fight in a a war because somebody enticed him to do so: he fought to defend his freedom, his family, and his way of life.
Don't oversimplify those things.