The answer as provided by the Book of Mormon is that we should do both.
First, Nephi sees the many nations and kingdoms of the earth. In those nations were living those that the angel refers to as "the Gentiles". To Nephi, who was part of the house of Israel, this would have meant that they were all people outside the covenant and lineage he had come from.
Next, Nephi is shown that the Gentiles create a great church, one that is opposed to God's purposes and aligned with Satan's purposes instead. Nephi sees that this church puts in bondage, persecutes, tortures, and kills people who believe in God.
The temptation here is to immediately wonder which "church" is meant by what is shown in the vision, but we must be careful not to engage in presentism (distorting historical analysis by applying our own present-day biases) to interpret scripture. The purpose of this vision was not to single out any one denomination or even any one religion. No such entity is specifically named. All this scripture points to is "a great church".
The angel clarifies what is meant. This church is a metaphor for any organization of the world that seeks to use its power to gain power over God's people, to corrupt them in any way, or to destroy them physically and/or spiritually. He also states that it is the "church of the devil", meaning that the devil is the founder of it, and that its motivation is pride and to get the glory of the world. The fact that it is lumped into one great church is meant as a convenience in addressing its influence in the world rather than an attempt to single out any one group of individuals having a particular religious belief.
Now we get to the really interesting part, for we learn that Nephi sees "many waters" that divide his and his brothers' seed from the Gentiles (obviously these are the Atlantic and Pacific oceans). Then, he sees a man who is influenced by the Holy Ghost to set out on the waters "even unto the seed of my brethren, who were in the promised land."
Stop for a minute and think about who Nephi is seeing. Who in our own history books "first" arrives on our continent and "discovers" the people living there? Why, it's Christopher Columbus, of course.
In the next verse, we learn that other Gentiles followed suit and arrived in the Americas in "many multitudes" and began to smite the seed of Nephi's brothers who remained, scattering them--which we, in hindsight, see as having been done in three ways: geographically, culturally, and spiritually.
14 And it came to pass that I beheld many amultitudes of the Gentiles upon the bland of promise; and I beheld the wrath of God, that it was upon the seed of my brethren; and they were cscattered before the Gentiles and were smitten.15 And I beheld the Spirit of the Lord, that it was upon the Gentiles, and they did prosper and aobtain the bland for their inheritance; and I beheld that they were white, and exceedingly fair and cbeautiful, like unto my people before they were dslain.16 And it came to pass that I, Nephi, beheld that the Gentiles who had gone forth out of captivity did humble themselves before the Lord; and the power of the Lord was awith them.
But, now we are reading history through the eyes, minds, and hearts of people whose descendants they were and who have a prophetic and divinely inspired explanation (not an excuse) as to why such horrible things would have happened to their seed. Remember that an earlier portion of Nephi's vision is replete with a fratricidal war of equal proportions perpetrated by the Lamanites against the Nephite people and eventually among the Lamanite people themselves.
Nephi explains to us in this and later writings that the Lamanites were reaping the consequences of actions previously sown. The lesson that Nephi, and later Moroni, teach us is that the Book of Mormon is meant to show the Gentiles that they are little different from the Lamanites, Nephites, and Jaredites. The Gentiles will be under equal condemnation and consequence from God if they do not repent of their sins (including the intentional killing and scattering of the Lamanite nations) and turn to Him while living in the promised land.
In the next post, 1 Nephi 13, Part II, we will analyze Nephi's vision of the Revolutionary and other Gentile wars and events in the Americas. We'll also look at Nephi's vision and interpretation of the development and influence of the modern-day Bible (no, it didn't just fall out of the sky one day as a single, chronological volume and land on Emperor Constantine's throne or Martin Luther's pulpit).
In 1 Nephi 13, Part III, we'll look at the additional books of scripture that God authorized to be written and how both the Bible and other books of scripture support each other in testifying of Christ in all the world...not just in Jerusalem.