Your therapist may have been referring to the way that a person identifies with and takes on the abuser/kidnapper's view of how worthless/hopeless/undeserving she (the captive) is. You don't have to say positive things about the abuser to have this term come up. If you adopted his beliefs about you and your situation, then that's what this is referring to. (I think.) Telling a potential rescuer that you are fine fits with this--it's aligning with the captor's worldview and power.

It sounds like you're doubting your therapist because of what you read on google? I would definitely tell her how you're processing the things she's said.