Maybe It's Because I'm Not Fat?

Many things that I have seen in this life seem like a mirror. I'm seeing somebody else do something that I worry I do just like them.
When the young woman expressed concern that a co-worker didn't like her, she expressed the thought that perhaps it was because the co-worker was obese and she was relatively thin. She went on to explain that most of the person's friends at work were fat, so possibly that could explain it.
It didn't sound impossible, except for one thing: The person explaining this to me is one of the more annoying people I have met. At first, she comes across as friendly, but then you realize that almost all conversations come off as some kind of passive-aggressive attack. Just about everybody that deals with her on a day to day basis, sooner or later explodes to her to just leave them alone. I swear she has the hide of an elephant, because none of that seems to dissuade her from doing these things.
The smart thing to do would be to tell her to stop these behaviors and she could start making friends instead of enemies, but as another co-worked announced, she is doing this wantonly and not by accident.
There are just some things you don't want to hear and others you just don't hear. I'm working harder to remember that.