Original sentence: Poles and Polish Jews from Soviet Union were subject of a process called "repatriation" (settlement within the territory of post-war Poland), but many of them who were imprisoned or deported to work camps in Siberia or Kazakhstan were frequently excluded
Edited sentence: Poles and Polish Jews from Soviet Union were subject of process called "repatriation" (return to Poland that moved westward), but  many of them who were imprisoned or deported to work camps in Siberia or Kazakhstan were frequently excluded