This is usually followed by shouts of things like “I didn’t do anything wrong...”I can't tell you how often I heard these exact words from my uBPDexbf. Every time he said it, I couldn't help but imagine a small child saying this over and over to a parent who was viewed as harsh or blaming. I think this is the hurt place they live inside. Almost like a cowering child who is yelling "it's not my fault!"
When we grow up and become adults, most of us don't feel the need to declare "it's not my fault!" We can take responsibility for our actions, and it is a sign of maturity to do so. In certain situations, of course, it's not "our fault," and we can simply explain why this is the case.
People with BPD are stuck at a very young developmental age, and growth is very complex and difficult. We will not ever be able to expect adult reasoning and behavior unless the person undergoes extensive therapy for BPD, and even then, recovery may be spotty.