If MANDAILING IS NOT BATAK!!! Where did the origins of MANDAILING come from???

If mandailing is not batak! Where did the Mandailing come from? Lately we have heard a lot of various petitions saying that Mandailing is not Batak. Even this petition has been presented by historians, anthropologists and traditional elders. Maybe after listening to the contents of this video all of my friends can draw a common thread about where the Mandailing tribe comes from.