Abuse is certainly one pathway by which people can come by BPD, but not the only way. What we refer to as an “invalidating environment” is the main pathway, and what this means is that the individual’s feelings and beliefs are made to feel untrue or questionable as a result of their environment and the people in it. Abuse can fall under that umbrella of an invalidating environment (e.g., sexual abuse by a family member - “I’m supposed to feel safe with this person but he hurt me”). Same with abandonment, and remember that Jenelle’s father left when she was young (“he’s supposed to love me but he left”). The invalidating environment can take other forms, such as a parent reacting badly when the child expresses emotions (e.g., “man up,” “stop crying or I’ll give you something to cry about”). I could believe that Barb might have created an invalidating environment for Jenelle in some ways.
So you’re correct that most individuals with BPD have suffered abuse, but even if Jenelle experienced no physical or sexual abuse, I’m not dubious at all about her probably meeting criteria for the diagnosis. I have seen more than a few patients in my practice who have BPD and report no abuse background.