"My mother (and sister, they were a team) was like that. I am the most principled person in the family (this disturbs their conscience). This is why your mother will not leave you be,...because you and your husband have always disturbed her conscience. Whenever somebody senses a lack of insecurities in another person (in other words, they see the other person has a clear conscience because they are principled, they start to feel uncomfortable and think that the other person might be better than them."
OMG! You have just told MY life story in this my family and my life in general as far as my relationships are concerned. My question to you is, since you are making sense to me, why does it bother people so much? I don't look at people as better or worse. I do look at character to see if they fit in with my own but as far as pointing the finger and saying " your this that and the other" I try my best not to do that, but when it comes to me people break their necks to point out any behavior that they may find "displeasing". I started to realize that I am also a principled person and like you said " it disturbs peoples conscience". So, what I do is treat people with a long wooden spoon. I limit my time with them. I thin that is all you can do with people like this. They hae issues they need to work on. YOU, I, Nor anyone else can help them. They have to help themselves.
To the poster: Do not feel bad for being a wonderful person. You mother in law? Can't remember! She feels poopy about herself. Dust your shoulders off and keep moving.