It seems that just as some on here are quick to point fingers of blame without having all of the facts, there are others who will defend the indefensible.
IF and only IF, this aircraft had an engine problem that forced it to shut down one near its origin point of LAX, and the crew elected to fly the aircraft full of passengers across North America, bypassing numerous suitable alternates and maintenance facilities, and the Atlantic Ocean in the middle of winter, with only 3 engines operating, then had to declare an emergency for lack of fuel and land at Manchester, I would not call them heroes. Of course, we have to wait for the facts to come out and this might not be correct, but let's not jump to conclusions from either side.
The crew might have a perfectly logical and legal reason for doing what they did. Let's give them that benefit. But on the surface, it seems that there might be more than a mechanical problem here.