"In the Interests of the Oppressed"

Given the state of America at the time of the Spanish-American War, we can more easily understand why discriminatory practices and racist divisions were still occurring contributing to long standing oppression of African Americans. Thanks to Faust, we well know that the Southern slave-holders had to be utterly defeated in America's bloodiest war and forced to allow slaves their freedom a brief time before this. A Southern Civil Religion had formed and treatment of African Americans had not much improved by the late 19th century. However, the Christian argument for the war on behalf of Cuba was one of humanitarian aid and dutiful intervention "in the interests of the oppressed" (McCullough, 31).
I find J.H. Garrison's remark terribly ironic: “no Protestant nation under heaven would treat a subject people as Spain has treated Cuba" (McCullough, 80). How do Americans reconcile their still discriminatory treatment of slaves with their humanitarian "missionary" efforts toward Cuba? It was publicly acknowledged that, "The rule, ‘Thou shalt love thy neighbor as thyself,’ is for nations as well as individuals, and all questions of public policy must be settled by that rule" (McCullough, 47). If Cuba is America's "brother" or "neighbor," how are African Americans not? Was this because American Civil Religion was essentially still Northern Civil Religion? Despite what they said, perhaps the Christ-like,  humanitarian effort was only recognized on an international scale?

Furthermore, would America not have considered Cuba an un-progressed people under any other circumstances? Did America not due to the fact that "most barely knew the location of the islands, much less anything about their history, topography, or population" (McCullough, 102)? Wouldn't that typically mean that America would automatically "other" them?