I honestly don't even know who Viola Davis is.
Neither do I. That's not the point. Not only is Viola Davis black, but she's a young actress that could receive a tremendous career boost from her victory. Same reasoning as that girl in "Precious" winning, Jennifer Hudson winning, Halle Berry winning, etc.
I never make decisions on the Oscars based on the quality of performances. Usually, I do better without having watched any of the films or performances.
Instead, I do it purely on an economics/political basis. Treat it as a business that is trying to get ratings and improve revenue for movies that also possesses well-known liberal biases.