Idealism is based on big ideas. And, as anybody who has ever been asked "What's the big idea?" knows, most big ideas are bad ones.
P. J. O'Rourke (2007). “All the Trouble in the World: The Lighter Side of Overpopulation, Famine, Ecological Disaster, Ethnic Hatred, Plague, and Poverty”, p.256, Grove/Atlantic, Inc.