I have to say that there is a lot of blame to go around here.
First, UAL management. A diversion from HKG to MFM is hardly an off the wall scenario. If you are going to carry 300+ passengers your first priority should be to take care of 300+ passengers. MBA degrees notwithstanding.
The Captain lost the high ground when he made moving the airplane part of a deal. You are legal or you are not. You are safe or you are not. Anything else comes the morning after with a call to your Chief Pilot.
But I do feel for the crew and passengers. Before I retire I would again like to ride on an international flight on an American airline where the management actually gives a d*** about running the airline.