People weren't just voting on the basis of the colour of the candidate, either in this election or previous ones.

The proportion of votes for Obama in all those categories - Non-Hispanic "white", Non-Hispanic "black", Hispanic ("white" and "black") and Other - was higher than it had been for Gore or Kerry.   

And both those candidates, though white as they come, also got the overwhelming majority of Non-Hispanic Black voters - the proportion of those votes that Obama got was not all that much higher.

There are no grounds for assuming that race was the main reason why a significant proportion of Non-Hispanic "white" voters continued to support the Republican candidate. And while Obama's "race" may have been an additional motivating factor for many people, there is no evidence that it was a major reason for the shift in voting patterns.