In reading these stories, it is clear that the author believed (I believe she passed away) that the Indian religions--or at least some of them--presented a preserved version of the ancient religion. Unfortunately, the Indians quoted in the book believed this, and rejected any of "the white man's religion" because they believed that God had commanded them to reject any external religion.
Upon reflection, I realize that this is a similar position to any other religion. Here is a general statement that I think any religion on earth today could state:
"Our religion is right, and it is preserved from our fathers. We have been commanded not to accept any external religion, because our religion is right as it is."
There is a significant problem with this attitude. It guarantees that those who possess it will never come closer to God than they are already. This problem is mitigated in the minds of those who possess it by some sort of assurance that, while their religion doesn't have power to bring an individual into God's presence now, it will do so later, sometime after death. A religion that does not have power to bring you into God's presence now will never bring you into God's presence later. If it has cleansed you of your sins enough to withstand his presence later, it has done so enough to bear his presence now. If you have not obtained his presence now, it is because you are not prepared to do so, and if you are not prepared to do so now, nothing will change once you die.
People ought to recognize that their lack of experiences with God is an indication that they are doing something wrong. If your religion does not bring you to hear God's voice, to experience his power, and eventually to see him, it is not right. You are doing something wrong.
God told Joseph Smith that all religions:
...were...wrong; and the Personage who addressed me said that all their creeds were an abomination in his sight; that those professors were all corrupt; that: “they draw near to me with their lips, but their hearts are far from me, they teach for doctrines the commandments of men, having a form of godliness, but they deny the power thereof.” (Joseph Smith History 1:19)
This condition is just as true today as it was in Joseph's day.
And my vineyard has become corrupted every whit; and there is none which doeth good save it be a few; and they err in many instances because of priestcrafts, all having corrupt minds. (D&C 33:4)Adam received his religion from God. It was experiential; it's highest purpose was to bring an individual into God's presence. Those who believed Adam's first-hand experience and did what he taught received the same experience. This is the way true religion is passed from those who have had experiences to those who have not: by getting them the same experience. True religion propagates through first-hand experience.
Yea, they have all gone out of the way; they have become corrupted. Because of pride, and because of false teachers, and false doctrine, their churches have become corrupted, and their churches are lifted up; because of pride they are puffed up. (2 Nephi 28:11-12)
In contrast, false or adulterated religions--those that do not possess power to bring an individual into God's presence--are proliferated from person to person through claims to authority.
Whereas any modification to true religion would result in the loss of first-hand experiences, robbing people of any experiential reason for adopting it, false religion can be further corrupted without any loss in propagation efficacy. People don't accept false religion because of the experiences with God that it brings. They do it to satisfy their pride, their vain ambition, their desire to justify themselves without actually repenting, etc. None of these things require truth, and so truth can be adulterated to any degree without losing them.
If your religious practice / understanding has not brought you to experience his power, hear his voice (literally), or see his face, it means that you either lack required knowledge (because your religion doesn't possess it) or you are doing something wrong (because your religion tells you to). Find yourself someone (in person or in scripture) who possesses fruits that you have not yet obtained, and try to do what they do. Seek God and ask him for guidance, discernment, and wisdom. Be willing to recognize truth in what you see while rejecting the error you see.
The Indians, the LDS, the Snufferites, the Catholics, the Baptists, the Methodists, the Pentecostals, the Jews, and everyone else will have to let go of what they treasure which is false in order for God to give them what they lack to encounter him.