Liberals' race problem
...It does explain democrat hostility toward minority conservatives. They view them as apostates and traitors to the liberal cause. While Democrats will still try to push their accusations of racism and bigotry about Republicans it is also much harder to do so when minority candidates in the GOP are also the leading candidates.
How strange it must be for people who comfort themselves with the slander that the GOP is a cult of organized racial hatred that the most popular politician among conservatives is a black man. Better to ignore the elephant in the room than account for such an inconvenient fact. The race card is just too valuable politically and psychologically for liberals who need to believe that their political opponents are evil.
Carson's popularity isn't solely derived from his race, but it is a factor. The vast majority of conservatives resent the fact that Democrats glibly and shamelessly accuse Republicans of bigotry -- against blacks, Hispanics and women -- simply because they disagree with liberal policies (which most conservatives believe hurt minorities).
Yet conservatives also refuse to adopt those liberal policies just to prove they aren't bigots. Carson -- not to mention Carly Fiorina and Hispanics Ted Cruz and Marco Rubio -- demonstrates that there's no inherent contradiction between being a minority (or a woman) and supporting conservative principles. And that fact is just too terrible for some liberals to contemplate.