"talking about your mental health" does not mean re-parroting your trauma. there's understanding, re-framing, forgiving, all kind of other things that go beyond the limited belief that talking just calcifies trauma.
venting is a form of talking about mental health. there are other forms that the problem statement doesn't apply to, like your examples. but the statement does apply to my example, therefore we can't say that talking about mental health is exclusively a positive behaviour.
Do you know a single person who has cured their mental health problem?