Ever lived in Africa (Afrika)?
No matter what you try and teach them they end up having sex even if they know that they have a 90% change of getting a disease which will either kill them or cripple them the rest of their lives.
They no longer have tribal leaders.
If we leave them alone and stop trying to save them they will eventually decrease their population and put power back into tribal leaders who used to control who mated with who.
I’m thinking “natural” population reduction - famines, disasters, not to mention warfare, diseases, etc. Do-gooders are pushing for zero population growth on one hand, not realizing foreign aid usually has the opposite effect.