Don't know much about Linehan but the adversarial thing seems to be her referring to what she DOESN'T believe in. It's not the T vs. the symptoms, or the T vs. the parts of the patient that need to change. I think she is proposing the intersubjective tough love thing instead (what a phrase !), where it is more like, a T can like and support their patient exactly as they are at that moment, but still want to push them to change... but it's not like a competition....