Shouting is used to achieve short-term results. We see it quite a bit in sports. Shouting is a method of conveying dominance over and instilling fear in the person on the receiving end. Do this now, or else. Apart, from getting someone's attention across the room, it's a tactic used when other methods don't seem to work. And while the quick result is often achieved (which begets more shouting), it's important to note the shouting act isn't for the person being shouted at...it's for the shouter. I've never met anyone who enjoys receiving a good tongue lashing.
One of the skills effective leaders develop is the ability to calmly process options and to respond without drama. The leader's focus is on making the process, the act, the service better and in turn help the people doing the work get better. The dignified approach is to enroll the group in the journey, which requires understanding and caring how people feel. A person feels like doing their best when they have value. And, almost no one feels valued when they're being yelled at.
Shouting is another form of the resistance, the force keeping us from doing the necessary work. It's the urge to go with a shortcut to achieve an immediate result...no matter the long-term effect. The hard work then, the most important work, is to put the resistance aside and to do our best work despite it.
If we remove the shouting, what do we do instead? Choose wisely.