[she's frustrated by his lack of the sort of real response she wanted to hear. It's not as if she expected an easy answer for just what had created Darth Vader, but she expected more than this. For such a large disconnect between the Anakin Padme knew and the Sith Lord Leia knew, she had assumed there was something more than this to cause that change.]

I'm not looking to blame Darth Vader's existence on anyone other than himself. [Well, she blames Anakin, as expected, but she still sees them as the same, and likely would for a long time, despite everything.]

Tell me what you do know, then. What actually happened?