The Kellogg Professor of Communications Studies at the University of Michigan and chair of the Communications Studies department, Susan Douglas, has published an article, "It's Okay To Hate Republicans":
A series of studies has found that political conservatives tend toward certain psychological characteristics. What are they? Dogmatism, rigidity and intolerance
 of ambiguity; a need to avoid uncertainty; support for authoritarianism; a heightened sense of threat from others; and a personal need for structure. How do these qualities influence political thinking?
According to researchers, the two core dimensions of conservative thought are resistance to change and support for inequality. These, in turn, are core elements of social intolerance. The need for certainty, the need to manage fear of social change, lead to black-and-white thinking and an embrace of stereotypes. Which could certainly lead to a desire to deride those not like you—whether people of color, LGBT people or Democrats. And, especially since the early 1990s, Republican politicians and pundits have been feeding these needs with a single-minded, uncomplicated, good-vs.-evil worldview that vilifies Democrats.
So now we hate them back. And for good reason.
Link via National Review Online.