They shouldn't have been allowed to board in an intoxicated state.
Yes, denying boarding is confrontational, unpleasant and sometimes difficult.
However it is the responsibility of whoever runs the cabin to ensure that apes like these don't get on, three sheets to the wind.
Besides, I can't imagine an instance at Qantas where a Captain wouldn't support the assessment of a CSM.
Not even the goons running QF CC management are going to take you to task over a delay incurred for this kind of incident.
Maybe things are different at, "onya jetstar"?