Yes, I'm well aware of the history of the food pyramid. It was in my science books in school. It was taught and talked about in the public sphere as if every expert on the planet agreed that the grain based food pyramid was undisputed among the scientific community. If that example is too far away for you, how about WMDs in Iraq. Do you remember how "every expert" said they existed and how if you were skeptical you were a national heretic?