We seem to have an interesting tension in Mormonism (and traditional Christianity, too) between universalism and exclusivism. On the one hand, we have a very inclusivist soteriology, in which all except a very few sons of perdition will be saved in a kingdom of glory. On the other hand, there are exclusive ordinances that must be performed by an exclusive priesthood authority in order to receive the highest salvation.
This tendency manifests itself in a variety of ways, scripturally and in the practice and teachings of the Church. A brief list might include:
The story of the City of Enoch seems to epitomize this tension: The scriptures tell us that “there were no poor among them” (emphasis mine). Does this mean there were no poor on the whole face of the earth? I don't think so. It seems that there was some exclusion going on, but that this did not prevent the city from being taken up to God. But we tend to view exclusion as a bad thing today. Are we justified in believing that?
This tension is also manifest in the seeming contradiction of Christ's words in the gospels: on the one hand, he is recorded as saying, “he that is not against us is on our part,” but on the other, he is recorded as saying, “He that is not with me is against me.”
What are we to make of this tension? How far should our desire to be inclusive go? When is exclusion desirable, necessary, ethical?