Fantastic Racism: In the universe in general, in many places. Species vs. species, meat vs. metal, augments vs. baselines, oxygen-breathers vs. methane-breathers, elder races vs. younger races, oh, and let us by no means forget the good old intraspecies kind. While not all species evolve with xenophobic jerkery coded right into the genome, enough do that this particular meme just keeps coming back.
The Imperials, by and large, eschew old-fashioned racism in favor of traditional Cultural Posturing and, in particular, sneering at the unContracted. Well, except for the Purity Crusade (who want to wipe out all non-eldrae, or at least non-Imperial, sophont life for being, essentially, a bunch of defective entropy-worshipping slave-cultist creepazoids and therefore not to be allowed to exist, especially if it might one day threaten its betters), but they’re a tiny group of, essentially, the whackos’ whackos.