Is she arguing or just discussing the topic that was brought up? Perhaps she is just giving her opinion. If she is defending herself, perhaps she felt she was being attacked or questioned. She may have self esteem issues. Personally, I prefer a talker to someone you have to drag every word out of.
Quit dealing with people like this. You are wasting your time. You communicate nicely and seem to be an intelligent person. Find some friends who are not into game playing ,as these tend to be. You will be much better off and they will have to find another person to scam.