What's the purpose of "Captivity" by Louise Erdrich?

"Captivity" by Louise Erdrich begins with a quote from Mary Rowlandson's autobiography, in which she tells of being captured by a band of Wampanoag near Massachusetts in 1676. From there, Erdrich crafts a poem that disassembles and questions the cultural stereotypes and expectations of the Europeans and Native Americans at that time. The Native Americans were, at the time, seen as ungodly savage beings, and Erdrich recognizes their tragic history through a sort of irony. The narrator of the poem, an unidentified woman in a similar situation to Ms. Rowlandson's, initially seems repulsed by the men, fearing that a connection may form between them: "There were times I feared I understood / his language, which was not human / and I knelt to pray for strength."
As the poem progresses, the narrator spends more time with the Wampanoag and forms a sort of intimate bond with her captor. She is brought home, but she is completely changed. Towards the end of the poem, the narrator begins to question her own worldview as well as the society and culture of her own people. She speaks of her husband's inability to farm properly: "Rescued, I see no truth in things / My husband drives a thick wedge / through the earth, still it shuts / to him year after year."
The purpose of "Captivity" by Louise Erdrich is to show the differences in the two cultures, English and Native American, particularly at the time, and to deconstruct the preconceived notions that one may have had of the other. It is certainly critical of the racism and dehumanizing behavior with which the European settlers treated the indigenous peoples they encountered. The narrator undergoes a spiritual and cultural transformation by the end of the poem, and the poem itself seems to show the humanity of the Wampanoag.