Its not so much that the SuperFriends team happened.... its how it happened.
For example, if Cleveland had the cap space..... had they signed Wade and Bosh and gone on to win rings.... I don't think anyone would hold that against LeBron. Why? Because it was LeBron's team and those pieces were ADDED TO him.
The problem (besides the whole FA facade, the interviews, the documentary, the tweets, etc) was that LeBron left to join someone else's team.
It was basically an admission on his part that he doesn't think he can be the guy.
Kobe would have never left the Lakers to form a superteam. He did, however, get a damn good team surrounding him in LA.
MJ never left/never would have left the Bulls.
Bird the Celtics.
Etc.
Had James even left to go to NY, or go to Chicago, or NJ... there'd have been less "harm" done to him in doing so - because on any of those teams, he's the guy.