I think that's because the authors are pro psychologists, all of whom long ago accepted as dogma that clinical psychology CAN make a difference in thinking/beha

I think that's because the authors are pro psychologists, all of whom long ago accepted as dogma that clinical psychology CAN make a difference in thinking/behavior, especially in reducing neuroses. While this change for the better usually isn't described as "changing your personality", to most non-pro-psychologists, it could be. I suspect it's just a matter of how much change, and how the change manifests. If one of the classic attributes of personality is sustainably reset to a different level, like trust or sharing or kindness, I'd certainly consider that personality to be changed. I haven't read the article, but that may be what it proposes.