A couple problems with this:
- One of the major polling companies, SurveyUSA, does not human pollsters, it is completely automated so as to eliminate any pollster bias. In the 2004 elections SurveyUSA was the most accurate.
If pollster bias was driving the mainstream polls in favor of Obama, we would expect to see McCain do much better in the SurveyUSA poll. Instead, the SurveyUSA polls have been strong for Obama
-It’s true that in certain social circles(Liberal Elites in San Fran and the like), supporting McCain would be social suicide. But the same would hold true in very conservative communitiesin reverse- particularly if it is a religious social circle- if you belong to a Christian church which belives in the value of life and marriage, you probably wouldn’t want people to know it if you were supporting Obama.