Ethnic make up is an ILLUSION

No, it's a co-efficient between cultural connection and genomic closeness. A Japanese man would never be considered Nigerian. At the genetic level it is expressed as expanded familial ties between shared ancestry. It's a medical hard science and not subjectivised to "World peace man". Ethnocentrism is the basis by which nations of people form democratic self determination. As soon as you pour 35 million Somalis into Japan the ethnic harmony has turned into division aka diversity. Divide and rule. See South Africa.

Ethnic make up is an ILLUSION

No, it's a co-efficient between cultural connection and genomic closeness. A Japanese man would never be considered Nigerian.