Now this is a GREAT leadership skill, they just handle it the wrong way.
Handling it this way is what makes it a terrible leadership skill. It's not hard to recognize problems. That doesn't take leadership. It does take leadership to address the problems without getting emotional or upset, without casting undue blame, without making assigning blame the focus of the complaints, and without casing insults or getting aggressive. All of that helps to communicate with other people and help them bring the best possibility for success. Bitching does all of that wrong. It tries to blame people for mistakes, it gets extremely aggressive, and it creates responses almost entirely from emotion. It's a terrible communication strategy, and it completely lacks any leadership elements.
If you want an idea, here's one: tell players that questioning why someone made a mistake is a terrible idea. It gets you nothing, particularly when the answer usually won't improve future play. Giving proposals for what to do instead and developing plans is a much more effective use of limited time and it actually has a chance of bringing a team together. Bitching and whining won't.