How often do you hear fans talk about Dale Hawerchuk's leadership? Or Peter Stastny's leadership? Steve Yzerman was vilified as being nothing more than a fancy points guy who could never win, and then he was surrounded by a bunch of hall of fame players and suddenly he became...a leader. It's all simply stories made up to create a theme because we love to categorize and label, and then ultimately rationalize an outcome.
Military victors are considered great leaders. Those who are defeated, meanwhile, are almost never held up as great leaders, but nothing is ever that black and white. Was Patton better able to inspire his men than Mussolini? I doubt it. It's simply that one guy won, and the other guy lost, so history deems the winner to be a great leader.
That doesn't even account for more nefarious things like predispositions to certain races, ethnicities or genders. Jonathan Toews is held up as the ultimate leader of men, yet on his watch, and quite likely to his knowledge, one of those men was repeatedly taken advantage of without repercussion. Notwithstanding this, Toews' "leadership" qualities don't seem to have taken much of a hit. Meanwhile, Sergei Federov is one of the best players to ever play in the NHL, yet all we ever hear about in Canada when it comes to leadership is Steve Yzerman. It's not hard to understand why.
Auston Matthews hanging out with Justin Bieber in July at worst makes him a terrible judge of music. It doesn't, however, speak to his ability to win a Stanley Cup or his ability to motivate those around him (which presumably is the primary marker of leadership). If he signed a contract on July 1 for 8 years at $8 million per season, every Leafs fan in the world would fawn over him as a great leader, a man who sacrificed "me" for "we". It's all nonsense. Toronto, like any sports team, will win because at some point the collection of players, and the convergence of completely unpredictable circumstances, will produce an outcome. Sam Lafferty won't score an overtime winning goal in a Stanley Cup final game because Austen Matthews is a great leader or a terrible leader. It will be because over a large sample size the athletes who perform the best as a group, and who get the most luck, brought the team to the point where Sam Lafferty is put in a position to get a lucky bounce and a goal.