Really? Sure, it was A villian, but talk about the forest for the trees... MNU didn't force the aliens into barely livable slums, we did. MNU didn't decide to evict the aliens to a concentration camp, we demanded it. MNU doesn't gleefully murder alien babies, we do it through the cheerful racism of Wikus van der Merwe.
Sure, MNU is evil, too, and it drives many of the plot points, but certainly the human race, composed of sleepwalking Wikuses, gets the lions share of the blame.
A couple of additional points - IMDB Sharlto Copley and Neil Blomkamp, the lead actor and director. Copley has not a single acting credit other than this film. Blomkamp (who is only 29) has never directed anything longer than 15 minutes. Certainly, Peter Jackson (the producer) had a hand in things, but this movie is an astonishing accomplisment for two completely unknown artists.
I found Copley to be one of the most convincing sci-fi protagonists I've ever seen. He portrays and elicits such a broad range of emotion throughout the arc of the film - rage, pity, joy, disgust, fear, all spot on, pitch perfect. It would be a crime if he isn't nominated for an Oscar.
Blomkamp's direction is equally impressive. The movie races along, the camera-work is stellar, and the aliens seem absolutely real and depressingly normal in a way that sci-fi films often miss.
Sure, the themes of District 9 have been dealt with before, but rarely in such an adept and engaging fashion. This was a great film, sci-fi or not.