From the LA Times:
And in her opening monologue, Oscar host Ellen DeGeneres even joked that if McQueen's telling of the enslavement of Solomon Northup didn't take the top Academy Award, voters could be branded as "racists."
Whether or not Oscar voters were motivated by fear of looking racially insensitive, or to correct a perceived historical wrong, can never be known. But one top Oscar strategist said that Academy Awards voters have a long history of honoring movies that take on the subject of race relations.
"Look at 'A Soldiers Story,' 'In the Heat of the Night,' 'Ray,' 'Guess Who's Coming to Dinner' and 'Sounder,'" said Tony Angellotti, reeling off the names of films that collectively garnered 30 Oscar nominations with nine wins. "This kind of socially aware vote for a movie that spotlights racism is rooted in the academy's DNA."
All the same, two Oscar voters privately admitted that they didn't see "12 Years a Slave," thinking it would be upsetting. But they said they voted for it anyway because, given the film's social relevance, they felt obligated to do so.
I haven't yet watched "12 Years a Slave" so I can't speak to the merits of the movie itself. (I was too busy with other films to catch it in theatres but have been planning on doing so soon now that it's been released for rental).
The voting practices outlined here are more or less why I tend to consider film awards meaningless. (It also seems problematic when people fail avoid issues simply because addressing them might be "upsetting"). 12 Years a Slave sounds as though it may indeed be somewhat deserving of its award, but Milk racked up a few awards a few years back despite having the most cardboard characters of any film I've seen in an awfully long time. That particular film's award seem to me to be explainable only by the politics involved.