The escapees are not POW's, they are not captured Japanese. They are from a relocation center, a prison camp set up by the U.S. Government for Japanese-Americans taken from their homes and businesses and interred for the duration of the war. The vast majority were permanent residents, most were citizens. The US Government effectively kept full knowledge of the camps from the general public for almost 30 years. After lawsuits and publicity in the 1970s, some stations removed this short from rotation. Some to prevent offense, some to further keep the secret. Other Stooge shorts have been treated similarly, mostly due to racial depictions common when the films were made but considered offensive later, and generally with the same intentions.
Columbia production reel #571.