I agree that it does not have the consequence that Klein sees in it, but the phenomenon seems worthy of note. As you suggest, grumbling out of context will not undermine elite rule. That is the point about elite-bashing - it is sublimated class struggle - grumbling at the particular excesses rather than the system as a whole. It is quite popular over here, as with the anti-Tesco campaign, or the perennial stories about corrupt politicians.
Redirecting people's bad experience of capitalism overall against one particularly obnoxious representative is a qay of reconciling people to the system itself. It plays the same emotional role as the anti-Semitic propaganda against usury did in pre-war Europe.