Comment by thinkingemote

The question then becomes how to convert a member of a tribe to ones own correct tribe. It's a very tough question to answer.

It's like spycraft during the cold war. A double agent must pass as being in both tribes for the good of their country. They literally isolate themselves from their homelands tribe to embed themselves in another. They are forever changed. They can't go back. In other words: to change another changes oneself too. It weakens ones own group identity.

Almost all people would never want to risk their identity to change another person for the good of their group. It's very risky and very painful.

Another way that the article suggests is to let people change themselves.