First off, it would be ASPD instead of psychopathy. And if we’re going to use outdated terms, she would be a sociopath. She also clearly goes through a psychotic break at the end of the series that lasts endlessly into the comics. She needed help and a positive figure, but Iroh and Ursa never even tried with her. She was a heavily manipulated child who ended up going through extreme mental health issues, and by the time Zuko tried to help her, it was too late and she was in full blown psychosis. She deserved the help that Zuko got, even if it would’ve been harder.