OK, I guess I answered my own question.
I changed the line at the top of styles.css to
Tags: blog, news
and it passes Theme Check’s check. These two tags are the closest to the type of site that I am designing the theme for.
It dawns on me now that this has to do only with the header comment at the top of the style.css file. Right?
My header has this:
Tags:
There is nothing listed there. Is that the only problem?