One of the biggest challenges to racists must be watching and listening to infants and small children. Oh sure, you can tell the Asians from the Caucasians from the Negroids, etc, and maybe a skilled anthropologist could pick up subtler things. But IMO without knowledge of their parents and culture you couldn't predict their future political/social behavior or proclivities by observing them. They all pretty much look and sound the same to me anyway.
It's no surprise that Germans weren't too awfully popular immediately after WWII. And having absorbed as much fighting and bombing as they had, there were plenty of German refugees. Many of these were preschool children, who were sent to places like Denmark.
And this is what happened to some of them.