One can be more moral than the other. Does not mean that person hardly has skeletons itself. But I know nothing about mother Teresa. Nor cared to follow her works or she did every waking minute of her life.
Fair enough. But by saying one can be more moral than the other, you're acknowledging that one can
INDEED be holier than another without the phrase being a negative. And that's really my point.
Some people live their lives in such a way that they are morally responsible. They may not be perfect, but moral perfection and moral responsibility are two separate concepts. So if a person lives a life where he/she is morally upright, then, yes, that person is worthy of telling others they need to attain to a more morally responsible standard in their conduct.