The purpose of the division of Germany was to give the Allies occupation zones in the former German Reich that would allow for them to ensure that democracy was firmly restored in the country. If you're asking why some people feared a reunified Germany, it was because the last time the country tried democracy, it failed and this failure was the first stone to one of the deadliest and most devastating war in world history. They believed that a reunified germany might attempt domination again.
I believe this would be segreation. This is a very sad thing that went on and can still continue to go on when the whites were segregated from the blacks. hope this helps!
