This is true of other generic groups. An Argentine doesn't like vague (or unvague) references to "Latin American" sentiments; academics don't like generalities about their political or even philosophical preferences.
Notwithstanding, there are the raw data -- the famous Lichter-Rothman survey of 1980, which disclosed that 80 percent of the media elite had voted Democratic in every presidential election from 1964 to 1976. A poll of voting by the faculty of Dartmouth revealed that, if found, Republican professors are kept in zoos and fed irregularly. The Media Research Center in Washington, whose curator is L. Brent Bozell (my nephew), is a lively presence on the scene and amasses evidence of Democratic proclivities.
But statistical compilations are without flavor. For that you need skilled writers with an eye for detail and for special piquancies. We have this from Rick Perlstein.
Mr. Perlstein, a young journalist, is himself an ardent enthusiast for the American left, but in his book on the 1964 presidential campaign, he saw it all and tells it all, including eye-popping accounts of the excesses of his own political tribe. "Before the Storm" is a book about Barry Goldwater's campaign for president. It is intriguingly subtitled: "Barry Goldwater and the Unmaking of the American Consensus."
What is meant by that is that Goldwater's disastrous electoral count in 1964 (he won only Arizona and five Southern states), was misinterpreted by hot-pants ideologues such as Professors Arthur Schlesinger and John Kenneth Galbraith as the end of the conservative movement. But something happened on the way to a liberal consensus: The conservative movement thought dead was in fact gestating, and 16 years after the defeat of Goldwater would bring in Ronald Reagan.