The Lebron hate is cause he had an unprecedented amount of hype in high school and entered the league and named himself The King. People immediately were rooting for him to fail without ever seeing him play. It's the sports media hype, people get annoyed with it and root for those people to fail (ie Tom Brady, Yankees, etc.)
The hype machine was 1/1000th of what it is now in the days of Shaq, Will, Jordan, etc.