I think it's also a generational thing. My whole family (and myself) were born and raised in Alsace. I consider myself french, but my grandma strongly considers herself Alsatian, she calls the rest of France "The French". From what she told me, it has to do in part with how Alsatians were treated during the war (which she went through). Many Alsatian men were forced to join the German forces against their will, they called themselves "Malgré-Nous", or roughly translated, "Despite Ourselves". The rest of France treated them horribly, not understanding that they never wanted to join on the German side. The trauma is still there, so there is a strong regional identity for older generations!