The "vision" is notable for the way the Second Coming of the Son of Man as judge is minimized and rationalized away in favor of a now all-consuming Universalism.
Such rationalization is a feature of religion, not a bug.
The Pharisees were liberal democritizers of Judaism with their synagogue system, expanding the availability of the holiness of the Temple priests to the hinterlands of Israel and to the Diaspora. Paul for Christianity expanded membership in the lost sheep of the house of Israel saved by Christ to the Greek-speaking Gentile world of the Mediterranean. Even Muhammad for the Arabs gave them their very own Book which rewrote the erroneous Jewish and Christian Bible in their own language. The Protestant Reformers of hierarchical Catholicism created a priesthood of all believers transmitted in the vernacular thanks to Gutenberg.
But Mormons would flat out save the entire human race, expanding the availability of salvation even to the dead. The specific impetus is the belief that the Ten Lost Tribes of Israel were scattered globally, multiplied, and are basically unknown even to themselves, and that the Mormon mission is to gather them in to the House of Joseph in America, the twin of the House of Judah in Israel.
It's not unlike the Muslim view of its own legitimacy asserted through Ishmael, not Isaac. Mormonism is to American Protestantism, particularly nonconformist Protestantism of the Second Great Awakening in Western New York, as Islam is to Eastern Orthodoxy, particularly Nestorianism.
It's as ingenious as it is unconvincing.
The Whole Earth Shall Be in Commotion