Do you really think McNair wants to lose? Why does it have to be about "wanting" to win? Why can't it be that he's just not very good at knowing how to win?
Just because someone wants something doesn't mean he goes the distance to obtain that something. I want a PS4. I can pay for a PS4. But there are other things I'd prefer to spend money on at this point in time. Doesn't mean I wouldn't want the game console. McNair wants to win, but if that means actually firing people he likes, he obviously prefer to keep his guys instead.