i don't view the guy as a quitter, just disappointed.I know at least as many guys who regret playing football as I do who regret hanging it up early. Many guys I played with won't let their kids play. The game is really hard on your body, especially when you play on the line.
McMullen gave four years to the program, no? I don't see how this is "quitting" when you have your degree and simply choose to start your life.
Sub point: if this is quitting, then every player who ever left early for the draft has quit on his teammates.