Trolls are not "people who have a different enough opinion"; they are people who insist on claiming their opinions as the truth even when it brings no good to the discussion.
Case study: there are frequently libertalians posts on Slashdot. Obviously, as nobody outside the US is stupid enough to lose time with such a bullshit philosophy, I don't care for such discourses.
But I don't have anything particularly relevant to say to counter them, so I do not waste everybody's time by flaming these posts.
Once, I wrote that Galt's speech "I owe nobody nothing" is so utterly stupid and so at the opposite of all that makes civilization and wisdom (which are both about acknolewdging one's debts rather than speaking like a spoiled brat taking for granted all the help he ever got) that it removes the need to read the rest of Rand's writings in order to understand how she's a self-inflated quack.
That's probably "different enough opinion" to many slashdotters, and it is agressively worded indeed, but that's not flame: it's an analysis of a speech, and it's an argument, which means somebody disagreeing with me can challenge it with arguments of his own, not only flame me or insult me.
And I wrote this on topic, I do not reply to random libertalian posts to explain them why they're wrong - I know they won't change their opinions, and I won't either, so I spare us all the trouble.
Climatic change deniers or bible-thumping creationnists do not usually come here with argumentation and a desire to listen to contradiction, but only to assert their beliefs.
That's what makes them trolls, not the fact that they are GW deniers or creationists.
(I chose to use the meaning of the word that TFA uses, even if "troll" has a precise definition, since the parent seemed to use the same misleading meaning)
