From the reference to Israel's covenants the vision moves to the great and abominable church, which has been an important theme of the vision. As first introduced, the great and abominable church had more to do with the Gentiles than the house of Israel. This great and abominable church is the entity which removed the plain and precious parts of the gospel from the Gentiles.
In a chronological "future history" of the Gospel in the world, it is interesting that we return to the theme of the great and abominable church after witnessing the events of the restoration. This appearance of the great and abominable church would therefore appear to occur after the restoration of the gospel, and thus is more applicable to current readers than to those soon after the restoration.
In this verse the vision sets up a dichotomy, and one or the other designation. All people are placed on the one hand or the other. This is an apt follow up to the previous note that the restoration of the gospel will lead to salvation or damnation. In the image of the two ways, all greys are subsumed into the symbolic black and white of the opposite ways. In this sense will all be of one "church" or the other.
Once again, since there is no know condition which currently would suggest that there will be only a Mormon and Roman Catholic church in these last days, the great and abominable church is a symbolic construction. It is also important to note that just as the sword's edge of damnation is a symbolic construction, so too is the edge of salvation. The implication is that the vision is speaking of the quality of souls here, and not church organizations on either hand.