To further distinguish between vegetarians and non-vegetarians, Allen, Wilson, Ng, and Dunne (2000) compared values and beliefs of omnivores and vegetarians as a means of exploring social values of meat. In the first of two studies, 158 participants completed a right-wing authoritarianism scale, social dominance orientation scale, and a vegan-omnivore scale. Results showed that omnivores showed greater right-wing authoritarianism. Right-wing authoritarianism is characterized by the ‘submission to recognize authority and dominance and aggression to persons of lower status.’ However, because the sample of the study consisted predominantly of omnivores, a second study attempted to further validate differences between meat-eaters and vegetarians with a larger vegetarian population. Of 324 omnivores and 54 vegetarians, omnivores valued self-control, responsibility, logic and equity, and social power. Vegans and vegetarians stressed the importance of intellectualism and excitement, love and growth, happiness, and peace, equality, and social justice. In terms of consuming food, omnivores tended to value reputation and practicality, while vegans and vegetarians tended to value expressiveness and affectivity.
Quote taken from http://www.vrg.org/journal/vj2006issue1/vj2006issue1beliefs.htm
I can see that this definitely doesn't speak for everyone. But I can see the truth in it.