I don't hate Lebron, but like others, I don't like how he carries himself and some of the decisions he has made. I do admit that he is the best player out there right now, but still lacks a lot of what past champions/superstars had imo like Jordan and Magic.
I think the dislike for him obviously began after his nationally televised "decision" to go to the Heat, which was D. Wade's team. This was seen as an easy way out instead of following in past superstars steps where they willed their team to win at all costs. They accomplisehd this by working on their games in the offseason (James worked on commercials and still couldn't shoot), leading by example, and continued to lobby management on building a championship team. He was more concerned with being an icon (i.e. going on 60 min talking about wanting to be a billionare, etc) instead of a winner. On top of all this, the celebration after signing with the Heat about winning 6+ rings definitely didn't help his image.
After all that hoopla died down and he finally won last year, I actually didn't mind him as much, but then the attitude, flopping, and crying began. What's even worse is his new thing that he references when he does interviews where he plays down how he isn't suppose to even be here according to statistics where he grew up and that he is blessed and has no worries. The way he says it though is basically meant to be a slap in the face to all of us normal folks who have to do a 9-5 and do have worries/bills, etc.
So this year, I think a lot of people got back on that bandwagon of not standing him again because of this. I personally can't see how he can be so smug after this series where basically everyone knows the Spurs gave them the victory, not the other way around. And common sense seemed to elude sportscasters when they forgot that Tony was hurt most of the series (especially in game 7 no matter what Tony doesn't want to share) and Green was sick in game 7 and the Spurs still came within 2 of tying the game to go to overtime. Yes, the mighty Heat might have won it all... but it was because of what the Spurs didn't do moreso than them being so great. The "Chosen One" won't ever admit this though and will continue to be his smug self.