Most trolling behavior is motivated by repressed feelings of insignificance, weakness, anxiety, or unhappiness. I view the conflict that this type of person likes to create as similar to what an arson does. It gives him a sense of power and potency to know that with a single match he can create an inferno. He doesn’t have to deal with the consequences but gets to watch as others do. He is insulated from emotional fallout while creating visible proof that he exists and has an impact on the world, that secret feelings of insignificance are unfounded.
No matter how a troll phrases a comment or question the goal is always the same. It is to transfer painful repressed feelings onto someone else. When you respond you are using positive reinforcement and not only guaranteeing more comments in a similar vein but also giving the troll exactly what he wants. You are feeding the flames, providing the very oxygen necessary for them to breathe.
Reactive hostility is an evolutionarily determined attitude where when we feel wronged or violated we quickly go on the offensive, seeking to reestablish equilibrium and protect ourselves from further attack. Psychological knowledge is useful to override this inherited instinct and take a more complex view of what besting your adversary really is.
If you can realize that the person who is attempting to sow discord and unrest secretly feels insignificant, weak, anxiety ridden, and unhappy you can completely ignore the attempts to transfer these emotions to you, forcing him to continue to struggle with them. Don’t let yourself be duped into taking on a state of being that doesn’t belong to you. The best way to stop an arson is to take away the match, not try to put out the fire.