Jane Yolen

Josef quickly learned not to let anyone know he was Polish because the Poles suffered dreadfully in German hands. For months, the guards refused to allow air into the Polish barracks, keeping the doors and windows shut whatever the time of year. Many died at night from suffocation.
He learned not to identify with the Jews, because they too suffered horribly in the camp […]
He learned not to identify with the Gypsies for they were the prime live targets of the Pathologie experiments […]
He was identified as a homosexual, a pink triangle. They were treated terribly enough.