I always go back to 'The Thriller in Manilla' is Joe Frazier a quitter? IMO he is not, the right decision was made. Accumulation of punches cause more damage than a one punch knockout, Oscar was spent by round 5 and had nothing left, he made the right call at his age and with a family and long career ahead of him in the promotion field.
The fight was not competitive and he didn't ever look like he could turn the fight around.
Tszyu didn't want to quit, his corner did it for him. Tszyu had some problems post fight if i recall so the right decicion was made there too. Tszyu was more competitive in his fight but there was no way he was going to knock Hatton out in the final round (particulary with his balls hanging around his ankles)
McGirt did the right thing with Paulie, he was never going to stop Hatton.