If I may ask, why the SELF-DOUBT? Is it because his original sentence better hides his inelegance of action?

Good question. For a moment, I wondered whether, in fact, the words I identified as sentences were actually fragments. I'm much more certain now.

I agree with and appreciate the various choices kleinbl00 offers. I love the notion of the tech writers' style guides. I'm suggesting that each of my students create a style guide of their own in which they note writing errors that they tend to make. Once they are aware that a particular habit is construed by me as an error, they can choose to use it if they are writing creative prose.

I want them to be aware that they have used a comma where a semi-colon or period is needed. Then they can make an informed choice, should they have a reason. Of course language is dynamic and authorities abound. Some of my suggestions to my students (such as to use the Oxford comma) are preceded by the words "While you are in my class."

Few university students have had detailed feedback on their writing. The first real feedback I had was from my thesis advisor in graduate school. So far, they seem to appreciate a careful reading, even when they disagree with me (as in the example above).

CORRECTION: Student was not disagreeing with me so much as feeling uncomfortable with the short sentences and wondering if he would gradually feel more comfortable.