My .02 cents....If I can get the crew members involved to play nice than I will. However, if there really is a personal issue and I have a choice of new crew members I'm going to exercise that authority. As Captain I simply cannot have two crew members on board who can't work together. In the event of an emergency I need to know without any doubt that the job and passengers come first. If they aren't professional enough to do their jobs in the first place in a rational, professional manner than those crew members can't guarantee to me that that would be the case.
This. Plus a formal, very strongly worded report. There is no excuse for putting the airline in this position either. Although the PIC did the right thing in many respects, as there was a concern over PAX safety.