What do they do so wrong?

: TL;DR second at the bottom.

Only the people that are stupid enough to take trolls seriously, actually get mass butt hurt and provide a great source of teh lulz to those clever enough to spot a troll. Trolls bring life into forums everywhere, stirring mass flame wars over something to stupid to be possibly taken seriously. If you spot a troll, don't argue with it, that means the troll wins and gets teh lulz. If a troll thread is recognized for what it is, and people don't post on the thread, the thread dies, and is never seen again...

The only real problem is when you present a genuine argument, usually an anti-drug one, and people get sooo much butt hurt they can't do anything except classify it as a troll thread (because only trolls can deliver butt hurt to junkies) and they delete it, then they can go on with their life on the run. Why does every website, from Yahoo Answers! to CTRL+ALT+DEL forums, from RS Forums to Newgrounds Forums, completely fail to distinguish troll from non-troll? Always classifying real threads as troll threads, and in-your-face-obvious troll threads as valid arguments?

TL;DR People suck at finding troll threads all over the world, so real threads get deleted while troll threads reach "at least 100" pages.

I think I'll answer my own question: Troll threads that cause butt hurt are easy to argue with, because they aren't meant to be valid arguments. Genuine arguments that cause butt hurt are harder to argue with, because it is much easier to post "OBVIOUS TROLL IS OBVIOUS" than to post something meaningful and actually try to debunk the opposition's opposition.