That's because many residents of Southern Sakhalin were immigrants from the inland unlike Taiwan and Korea, and it was considered proper that the laws of the inland were applied to the immigrants without modifications.
これは、台湾や朝鮮とは異なり南樺太は内地からの移住者が多かったため、内地からの移住者については内地の法令をそのまま適用するのが相当であったためである。