Pace
You are right about the internet perhaps allowing people to say things that they would never say face to face. As for what it takes to be a troll, well I think Jabowacky met the test, not because he questioned my competency ( my wife does that all the time
), but rather he made several posts along the lines of
"Here is a question, I won't tell you what I think is the answer, you post what you think and then I will pronounce on it worthiness"
When posters do this it is clearly to bait the audience into a reply whereby they can publicly humiliate them by rubbishing the poster. These posts only purpose is to attack and disrupt the thread narrative so that the originator gets an ego boost. That IMO is trolling and jabawocky was doing it.
I think Peter337 is right, unlike many trolls, I think jabowacky probably does have the knowledge and experience to provide real value to this forum but as long as his attitude is "I am right, you are wrong, I don't have to explain myself and no discussion is necessary or desired" then him going NORDO is a good thing