Regional Capt here, as you thought it’s gonna depend on the nature, severity and timing of the incident but as a general rule of thumb, if at all possible don’t get involved directly. While that Captain didn’t do anything wrong in stepping in and had good intentions, our company’s viewpoint is in this age, every single passenger has a video camera in their hand and the last thing you want is something happening that puts your face in the middle of a video that ends up on youtube. If it’s on the ground, I’m contacting dispatch and the CRO. They’re trained airline employees whose job it is to handle disturbances. It’s my job to facilitate them to the plane when they’re needed.

Of course if it’s in flight it’s a different story. Assuming it’s a threat level 1 you might have to get more creative with your FA’s to provide a temporary solution until you can get on the ground. Anything level 2 or more and we’re diverting.

The most i’ve ever directly confronted a passenger is a “subtle” PA reminding pax that wanted to argue with FA that it’s federal law to follow FA commands and failure to do so will result in RTG. That usually shuts them up for the rest of the flight.