A lot of people dislike him because of the fact everyone was so quick to crown him the next Michael Jordan before he ever did anything. Now a lot of it is because of him leaving Cleveland in the manner he did.
Because they are just haters. A haters job is to hate so what do you expects. I bet it only makes him feel good because he knows that haters always have his name their mouth. I love my haters too. When you have haters you know your doing something good. Haters only hate because they see something they want or can't get.
The hatred started when he left his home team to join another team and people thought it was not cool to do that. He also received a lot of negative criticisms because he had a bad performance on his team on the last game before his move, since it is claimed the team needed him to win. Personally, I do not think people are justified in criticizing him so much since he was a free agent and could move to another teams and he did finish his contract before leaving the team. He is a good player and people should give him credit for his talent.