"Troll" has been watered down by some people to the point where it is used on everyone who disagrees with them.
In this case, the guy asked a question that he already knew the answer to in an attempt to make Jobs look bad by being the messenger.
Jobs evaded the question, instead of answering it, which was the only way to save face. With trolls, this is almost always the case, because they set up their question in such a way that there's no good answer to it.
I've always considered it as someone who is trying to push your buttons, get an emotional response from you, make you mad. Making someone look bad is not necessarily trollish, they may well be bad and the comment is attempting to reveal the persons true nature.
Also, I don't think the guy really "knew" the answer to the question and had legitimate gripes as you would if a project you've been working on for the last x years was suddenly canned.