What it has to do with the "cultural erasure" I quoted specifically? "Who owns the land" is a different problem that is not made simpler by the fact that the land is subject to tribal conflicts.
You have to realize their culture is not being lost mainly from people wanting to leave for a more convenient life. These small communities are not just culturally isolated, the are also physically isolated.
People with modern weapons (The Indonesian National Armed Forces) can basically do whatever they want there. And according to Wikipedia, that's exactly what they've been doing: