It's not their land, they don't even appear on colonial maps. They migrated out of Rwanda, Burundi first in the 19th century to escape taxes and they were welcomed by the Bashi, Balega and others natives of Kivu. Then other who fled violences in Rwanda and Hutu takeover joined them but they imported their tribalism(Hutu vs Tutsi) in Congo and strated claiming the land which wasn't theirs to begin with. The fact that they were helped by Rwanda afterwards which are considered the enemy by most congolese is contradictory with their aim to be accepted as congolese. What's needed is a growing presence of congolese forces, institutions on the ground and the respect of traditional lands. As long as the congolese government doesn't control well it's eastern territories, it will go on