I have often heard it said that everyone is a Liberal when young and a Conservative when old. This is partly true, usually when the world changes around people, they tend to cling to what they knew when young, out of fear of their own obsolescence. The world makes what was Liberal at one point, relatively Conservative at a later point.
So, why do Liberals tend to despise Conservatives? There is an arc of change that a person’s life tends to follow as they grow into Conservatism, each point in that arc comes with a characteristic that more open-minded people find offensive.