Dick, the question was about reporting him to the FSDO, not whether a CFI should be a nice guy or have a good personality.
Do you think you could get another lawyer, or CPA, or plumber disbarred just because he was not a nice guy and you had a persoanal dispute?
We don't even know what the dispute is over, and we only can assume which side is in the right.
In the past there have been cases where an FBO or full shop would try to get a small repair A&P kicked off the airport. The small guy may do just as good or better work in his hangar or out of his car trunk( Matt G does it out of his motorcycle trailer) and the big shop sees it as unfair competition, because the independent has less overhead cost.
When you don't know what a dispute is about, it is most likely to come down to plain old money, more so than safety.
Was the pilot an unsafe pilot or instructor before he made the nasty comment to our guy. If so, why didn't someone report him then? Is it only after the comment? I don't think there is any FAR that deals wth nasty comments, if you can find one let me know.
If a jackass is given enough rope he may hang himself , just as finally as to Bob Knight who knows all about basketball, but is still a bum.