Mularkey - He is where the Giants coach was last year. Despite any statements to the contrary, it's all about next year now. He's got to get his youngsters some game experience and some data for off-season evaluation.
Moulds - he said it early in the year: "I want to win now". I think he knew even then that this would be his last year here so he has absolutely no interest in the long-term success of Losman or the franchise. Since it's now pretty much painfully obvious that there are no playoffs in the immediate Bills future, he's basically playing for his next contract.
So Moulds needs stats and Mularkey isn't inclined to give them to him. Add to that the fact that Moulds stabbed the guy with control of the ball (Losman) in the back, and it looks like Moulds is up shitz creek without a paddle.
Don't get me wrong - I have a Moulds jersey and I've loved what Moulds has done for the team for the last 10 years, but I'm going to support the guy with the long-term interests of the team at heart, not the guy worried about his next contract somewhere else.