Captain = Pilot in Command
It seems pretty simple to me. If any F/O can't accept that in all cases, unless the safety of the aircraft and occupants would be put at risk, what the Captain says is what goes. The comment that " it is not the PIC's train set but the Company's" is, in my view, utter crap. The Captain bears the ultimate responsibility for the safe conduct of the flight and it is his backside that will be kicked if he allows his F/O to get away with refusing a reasonable request, such as "come on to a heading of ..... to give us 20 miles from that buildup". It may be the F/O's leg, but it is the Captain's aircraft.