“Savages” more effectively and more universally implies that the people so named are incapable, in their present state of understanding a liberal constitutional order, and must be repressed violently. “Niggers” carries the same implication, but only if you buy into white supremacy in the first place. “Niggers” is (aptly) threatened with obsolescence-- “savage” will live on, though it will describe acts of individuals, rather than societies.
