So what was behind his hatred of Sarah Palin?
I may be mistaken, but McCain was not always so angry at Palin and that his attitude towards her changed in the last few years of his life. Again, I think that the cancer could have been affecting his emotions as well as other personality traits.
Pure jealousy. People were coming out to see her, and hear her. She was the "buzz". She was better looking and smarter than McQueeg. Without Sarah, McCain couldn't draw a crowd.
2019, McCain is dead; Sarah Palin lives.