The Captain is the crew member, delegated by the company, to be in overall charge and accountable for the safe, professional and timely conduct of the flight. He/She is required to uphold issues of corporate policy and safety.
In that role the Captain will, almost certainly, delegate roles to key members of the crew, i.e. cabin security and conduct to the No.1/CSD/PU etc, 2nd in command to the SFO. This might well be done transparently through company procedures, however the buck stops with the Captain. The Captain has the ability, written in JAA law, to override ALL decisions made within the aircraft if he/she feels there is a need to do so. They don't even need to justify it to the crew member, but probably will have to on the ground to the management.
In the event of an incident/accident the Captain is accountable.
There are many, many ways to skin a cat, personally I think I get the best out of people when they are on-side to my cause. I am also very willing to listen to the advice of those who have worked in that environment for years. Unfortunately this doesn't always achieve the desired result as there are belligerent people out there. At this point I would have to use the authority invested in me by the company. If that comes down to the " I'm the Captain, you will do it this way" then so be it. It would take a long time to get to this point but it may well happen. Far from being a poor CRM example, it probably comes up as a good CRM example when you factor in that all other approaches had been made and it is the only possible way to achieve your aim.
You can please some of the people some of the time but not all of the people all of the time.
If you are unsure of this, re-read your manual and find the definition of Aircraft Captain, it states it all in there.