It seems to me that most people who think the CM handled this wrong are the people who are not and have never been CMs, or at least attractions CMs. He very likely couldn't enter the theater for one reason or another. If one of my indoor rides breaks, I can NOT enter the ride (at the risk of termination) to begin evacuating without managerial consent and without shutting down and locking up the ride system and taking the key with me, and leaving my ID so everyone knows I'm inside. CoP is a show, yes, but it's also a moving ride, and anything that moves is operated VERY differently from a show. At the Tiki Room, sure, a CM can just go in and tell everyone to leave. But at CoP, everything changes because it is, in fact, a ride, with moving parts, and people can be injured if they enter/exit when they're not supposed to. Obviously they can't begin ride motion if someone has one foot in the moving theater and one on the stationary ground outside.
I was at Small World a few months ago and a CM yelled at a guest because he exited his vehicle early into a restricted area by climbing through ropes. It may seem like nothing because the ride has no lapbars, but had he lost his balance and fallen into the track, he could have been seriously injured by the wires in the water or by the moving belts or the pumps, or might even have drowned. Or he could have been hurt even if he fell back into the boat.
Definitely. If guests are misbehaving, and continue to do so after you tell them not to, you do have to raise your tone, because people are more likely to listen if you sound more serious and threatening. Using the soft-to-stern method is pretty common with Parade Audience Control, you'll notice. And I probably would have been pretty ed off too if I was that guy. CMs are people too, and I get angry sometimes.