I know a lot of people would act as if they were supporting the friendship, more than what they felt was "right". I think this is especially true between women b/c many can't be as straightforward as men seem to be with each other. Of course, that's JMHO.
It takes courage for a friend to tell one that she's wrong. That's why many will listen more than express their own feelings to the walk -away.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!