It can be used to describe Briar per wiki. She was a victim of Magneto's terror and sympathized with him.
https://en.m.wikipedia.org/wiki/Stockholm_syndrome
Stockholm syndrome has also come to describe the reactions of some abuse victims beyond the context of kidnappings or hostage-taking. Actions and attitudes similar to those suffering from Stockholm Syndrome have also been found in victims of sexual abuse, human trafficking, discrimination, terror, and political oppression.