I reviewed "The Book of Mormon" musical on its tour stop in Salt Lake City:
The writers of "The Book of Mormon" musical focus their story on two groups of people, but it is clear from the text that they, themselves, are outsiders of both groups.
The first group (and the one that gets the most respectful, nuanced and researched treatment in the play) are missionaries of The Church of Jesus Christ of Latter-day Saints. The second group, getting painted with more stereotypical simplicity, are poverty-stricken Ugandans.
I don't take issue with the fact that Trey Parker, Matt Stone and Robert Lopez have brought forth a text that uses a people and culture other than their own to explore big, important, life-affirming ideas -- I would argue that Joseph Smith did the same thing with the real Book of Mormon, which, as a text, features Native American characters presented through a white, 19th century lens.