the following is based on personal speculation so once again feel free to correct me if i get this wrong while there are some surface similarities between racial hygiene and ethnic cleansing i believe that the concept of racial hygiene did not play a major role in the expulsions documented in this article the major unique feature of racial hygiene is the concept of race and genetics eugenics this concept argues that you are who you are by dint of your parents race and genetics and that what you think and how you act is irrelevant to the pollution caused by your inferior genes thus hitler could argue for an aryan super race that was polluted by jewish slavic and other inferior races if you had any forebears from a non aryan race you were suspect in contrast ethnic cleansing is more about removing those of a different ethnicity where ethnicity is usually marked by language religion and customs those considered to be a different ethnicity might be of the same race e g hutus and tutsis in rwanda it is hard to argue that poles and germans are of different races unless you are a nazi to most people they are just different ethnicities of the caucasian race it is similarly hard to argue that the various ethnic groups serbs croats bosnians in the the former yugoslavia are of different races as far as i know the major differences are language and religion as a thought experiment consider the case of a german woman married to a polish man in the first half of the th century if the family spoke polish at home and raised their children as poles i e polish speaking catholics would that family have been expelled i doubt it if you agree then you can see that the expulsions of ethnic germans may have been motivated by ethnic cleansing but not by racial hygiene hope that helps