That was humorous, but not exactly fair or kind. After a bit more surfing I found an article on Leftwing Pathology that posits that left wingers are essentially psychopathic. I will bypass the commentary on this page because in general it is name calling and not productive. But I do see how this is completely true from the conservative perspective.
Conservatism, most basically, is a limbic or mammalian mindedness emphasizing deep emotional connections, visceral aversions, and a strong instinctive sense of rightness vs wrongness. Liberalism is neocortical, involving the ability to weigh conflicting theories and integrate disparate data. To conservatives, liberals are immoral, or even psychopathic because they don't act from their hearts and guts. Liberals think about it, and make decisions based on information. The liberal method doesn't appreciate the power of people's personal attachments and belief systems. It hurts people's feelings. To the liberal, conservatives are dimwits who can't think rationally about anything. Of course the conservatives feel that they are the rational ones, they just consider different things to constitute "information".
It's about as bad as trying to get Israelis and Palestinians to talk to each other.
Conservatives feel a great deal more emotional pain when they are asked to act contrary to their own values. Liberals are expert at rationalizing--or neocorticalizing, if you will. Liberals are capable of acting more like a psychopath and being indifferent to pain both inside and around them.
But there's a spectrum. Some people are nearer the middle between emotional/instinctive/believing and intellectual/rationalizing/skeptical. Some can see both sides. Our limbic systems are intact and we can love deeply and hold values that matter, at the same time that our neocortices are developed enough to see that sometimes fairness that hurts is better in the long run than unfairness that feels safe and good. Maybe we could spend a little more time and energy trying to understand and be human to each other. We may not be able to develop policy that satisfies the deeply held attachments of conservatives, but we can at least acknowledge when the situation calls for deeply painful compromise, and try to be kind. The liberal who can't understand conservatives is more foolish than the conservative that can't understand liberals.