I didn't realize that Dejesus was referring to Lebron's leadership off of the basketball court. I'm also not certain that philanthropist is a synonym for leader.
I don't want to get into politics in this forum because I despise them with the heat of a billion suns.
Simply put, though, James has used his platform to speak out on issues that he deems important. Whether you agree with his views or not, he is incurring a potential cost (in actual dollars) in doing so by scaring away sponsors and other opportunities by speaking up.
It doesn't hurt that the NBA, unlike most other professional sports leagues, supports its athletes in speaking out. However, most modern professional star athletes, and especially those who are the faces of their sports (e.g. Peyton Manning and more recently JJ Watt from the NFL) tend to "stay in their lane" so as not to anger the fanbase and advertisers. James, and Kevin Durant to a lesser degree, chose not to play it safe. And while they are both rich enough that the opportunity cost of sponsorship money is relatively small, they are clearly risking financial upside in speaking out.
That defines leadership to me though I am curious what your thoughts are. Do you think that James is unworthy of being called a leader?