I have heard that the reason people like to receive constructive comments on their blogs is that it can lead to an increase in Ad Sense earnings. Experts say "Blog comments have powerful SEO, networking and traffic benefits." (https://www.matthewwoodward.co.uk/seo/link-building/blog-commenting/) Based on my logic, that can, in turn, lead to increased earnings.

Some people (like me) publish responses or comments to other articles o their profiles. Those comments are called "stories" just like the articles. Why can't comments or responses earn?

I wish Medium site owners would reconsider this. I say "reconsider" because I already asked Medium Admin about this. The answer was "NO". But I'm going to keep asking. You never know. LOL.