I hardly consider the words of a SINGLE officer (who has a mind of his own and clearly has issues) as an indicator that the entire Sith/Galactic Empire "hate aliens."
I can't speak for Sith, but it's a known fact (not sure from EU, or movies) that the Emperor hated aliens. If that was a trait common to all Dark Lords of the Sith, then I can see why there aren't any sith aliens.
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Dude that aint true the emperor's own body gaurds were alien!!!! If he hated them why would he trust his life to them.?
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You mean those in fully red uniforms? I can't recall seing anyone of them without a helmet to verify that your claim.
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Its in the Trawn Trilogy they are the lil grey dudes that try to capture Luke and Leia in the first book.