Seems like an overreaction on the therapist's part. I wouldn't feel safe with a therapist who lacked judgement and who threatened to lock me up. No one needs to be threatened with incarceration for expressing anger towards someone. OP I'm not sure what your distress level is but I'd encourage you to find a support group of some kind if you can't find/go to another therapist. I know sometimes we feel desperate and think anything is better than nothing. I understand and I've been there.