nathanbedford has a interesting theory about it. He said:
“The Billy Budd effect. If you recall your Melville, you will know that Billy Budd was a figure of good whose very presence antagonized the first mate who persecuted Billy Budd unmercifully. The mate was driven to do this unconsciously because the mate was a figure of evil. The mate had his demons. So it is with the left in America today, they are driven to a visceral hatred of Sarah Palin because she is the 21st century figure of Billy Budd. Sarah Palin committed an unforgivable affront, she knowingly carried a Mongoloid to term. This cannot be forgiven. This is the ultimate reproach to the entire belief system of the left. Sarah Palin need not even open her mouth and she is hated with a cold and unremitting fury.
This is why I said that the left hates Sarah Palin not for what she says or how she appears on television but for who she is. The left must react as evil always reacts in the presence of good. Like the second mate, they must persecute Sarah Palin and they do not even know why.”