Many liberals assumed Barack Obama was very progressive and would govern from the far left because they interpreted his call to "change" in their own terms. When Obama proves himself to be the pragmatic compromiser (that's what he meant by "change") his words clearly indicated he would be, they feel betrayed.
Many shoppers at Whole Foods assume that because the chain promotes organic, sustainable and local foods, and a lot of the staff looks cool, that its management is politically on the left. The fact that Whole Foods is a capitalist success story, built on aggressive competition and acquisition of every formidable foe, notwithstanding, they feel betrayed when its CEO proves to be an Ayn Rand disciple.
They assume that anyone who adopts the ethic born of the hippie era shares their world view. They are shocked that someone might believe in protecting the environment from a conservative political point of view, or might be "liberal" on one issue and "conservative" on another. Knee-jerk reactions from either end of the spectrum are typical but not helpful.
Whole Foods CEO John Mackey's recent opinion piece in the Wall Street Journal opposing Obama's approach to health care reform has angered many of his customers, some of whom are organizing to boycott the store. The fact that he presented the piece under the company banner is either very courageous or very foolish, and it was certain to bring such as reaction, whether fairly or not.