Suppose the people of group X are a blight on society. They may not be uniformly bad, but statistically speaking, they’re trouble. Perhaps they’re criminals. Perhaps they’re parasites. Perhaps they’re bad voters. Whatever the specifics, they’re proverbially “screwing up America” (or whatever your country happens to be). What should be done? Here are some remedies, in descending order of brutality.
Murder. Round up the members of group X and wipe them out. If they make any converts, murder them, too.
Sterilize. Round up the members of group X and destroy their ability to have children. This does nothing to reduce their currentpoor behavior, but — in the absence of rapid conversion — ensures group X will eventually become extinct.
Exclude. Enact immigration restrictions to keep members of group X out of your country. This does nothing to undo the harm that group X currently inflicts. Nor does it prevent the harm future generations of X will inflict. But it does effectively contain the social damage group X inflicts.
Brainwash. Subject members of group X, or perhaps just their children, to mandatory “re-education” to suppress — or at least dilute — their identity.
Censor. Forcibly silence members of group X to prevent them from spreading their identity by speaking or writing.
Disenfranchise. Deny members of group X the right to vote so the political system ignores their wishes.
The Vilani, of course, are canonically good for all six, but are famed for option one (with some personality rewrites on the side). The other Imperial humans have their own preferences: for example, in the Empty Quarter, Islamic societies rarely go for sterilization, while brainwashing is unlikely in Hindu cultures. Exclusion is absolutely everywhere, as is disenfranchisement, in the Empty Quarter.
Also: who is group X, and how are they defined? For the Vilani, they are those who refuse to conform, who insist on their disgusting innovations and refusal to uphold The Traditions.
For the Solomani, X are those who are genetically impure… but in the Empty Quarter, the Muslims place great weight on religious identity, as well as clan ties. The Hindi, in contrast, generally put less emphasis on racial purity than the rest of the Solomani, due to their panentheistic convictions.
(On the other hand, the Hindus are quite happy to place all species on a continuum of spiritual purity, with some species (like humans) standing above others (like the Vargr), just as some castes are above others.)
For strongly indvidualistic societies, the question may well not apply: but Vilani, Arab Muslim, and Hindi cultures are strongly collectivistic. (And so are the Bwap!) It is tribal identity that matters, not the man himself. This collectivistic focus is strongly tied to warfare (for both tribal protection and the tribal domination of others), and the distinct lack of a legal code that treats outsiders as of equal worth to insiders.