ALWAYS vs. NEVER Seeing Unlabeled Multiple Personality in Literature: Which is ridiculous?

It would be ridiculous for most literary criticism to always focus on signs of unlabeled multiple personality the way I do in this specialized blog, because it is not a major issue in most works of literature.

But it would be equally ridiculous for anyone’s literary criticism to never raise the issue, because it is a significant feature of some great literature and a reflection of the author's mind in most fiction.