I can't explain why I used to root for Jimmy Connors or Ilie Nastase over Bjorn Borg, or why I root for Tiger Woods over Phil Mickelson. Sometimes logic doesn't explain why I would root for someone who, on the surface, seems to display values that are not aligned to my own. I can't explain why there are at least four guys on the Heat that I dislike more than I dislike Lebron, or why any Laker is atuomatically despised and horrific (until they become a Celtic). The bottom line for me is that I accept that I don't really know ANY of these people. The players that I think are good guys may be despicable in private; players that I think are rotten people may have an endearing and kind side. Bottom line -- I don't really know any of them. It is possible that Lebron is a monogamous, family man who is generous and thoughtful to friends, relatives, waiters/waitresses and the kids down the street. But it's our natural and, to some extent, chosen perceptions that end up driving our rooting interests.
If Lebron played for the Celtics I'd be a huge fan. For now, I think he is an all-time great player who is the first all-time great to fully grow up in the glare of the 21st Century media spotlight. He has responded by being a hard-working, ball-sharing leader on the court, and a law-abiding citizen off the court. Additionally, he appears far more mature at 29 than he was at 25, and I expect he'll grow into a fine, humble and articulate NBA statesman. He belongs on the NBA Mt Rushmore and he can hold his head high amongst the others as far as I am concerned.
But then again, I don't really know him.