Actually cognitive therapy shows why it won't work. The change in cognitive therapy comes from a process through exercises to change thoughts, question beliefs, alter maladaptive behaviors.
If you imagine beliefs people have as reinforced by a web of other beliefs trying to find a middle ground will run into a million excuses why the original position is right. The troll (who often has no clue they are a troll) won't change their opinion in the moment - their beliefs will change gradually then they will act as if the new position was what they believed all along. The worst trolls have personality defects or don't get out enough to have social skills.
The attempt to use intelligence is more likely to defuse the original intention (to make themselves feel better or superior through antisocial behavior)