He creates a toxic atmosphere wherever he goes because he "just wants to win." High expectations are good, as long as you offer a high level of support. That's what makes great organizations of any kind. The problem with LeBron is that he offers zero support, and high expectations combined with no support is just bullying.
I mean, at which point in the past decade can you say that a LeBron team wasn't in some kind of turmoil? Even when they were winning, it was always some kind of instability. No one is ever safe; not teammates, not coaches. The moment something isn't going his way, he's throwing people under the bus and passive-aggressively asking for changes. His last season in Cleveland, he sent his coach and man sidekick to the hospital with anxiety. Last year with the Lakers, he said all the right stuff when he signed about how he knows the team is not a contender and how he's happy(at this stage in his career) to mentor the kids and help them develop.
What happened the moment they ran into difficulty? He was talking smack about the same kids, and then trying to force a trade for a superstar. We all know how that ended. Sure, it might be nice to play with LeBron when you're one of the superstar buddies he likes to team up with, but an NBA team is at least a dozen players. It doesn't look that fun to be one of the other guys. The Lakers are already being anointed as the 2020 Champs by bookies and journalists. What happens when there is inevitable problems during the season? What happens when the don't win the championship, which they probably won't?