Rainboe,
a Captain with years of experience chose a particular course of action. Someone reading the sparse information here is in no position to say they know a better way! And I'm not so sure silence speaks as loudly as you think!
I do not think the other two pilots would have allowed the Captain in question to remain in command and the aircraft to depart KMIA if they had felt he was not capable of command.
I find it interesting that the unions involved (assumption on my part) are being very quiet about this matter.