There is no hard-and-fast definition of trolling.
In one sense, it is like obscenity: "I know what it is when I see it."
In another sense, like beauty, trolling "is in the eye of the beholder."
Trolls do not admit that they are trolls. They are filled with passive aggression, and they love nothing better than to fill post after post with exquisite explanations of why they do not deserve to be thought badly of.
It is not possible to end an argument with a troll. Arguing endlessly is their bread and butter. At some point, the right course to take with them is to put them on hand-moderation or ban them altogether.
The moderators decide who is and who is not a troll. We call 'em as we see 'em. Our decisions are not subject to appeal within the Forum.
Please don't feed the trolls.