You seem to be awfully confused about the meaning of troll, Contrex. But why would an adult ever use such a childish pejorative anyway?
"Troll," in the context of message boards and the like, describes somebody who is posting just to be confrontational or to raise hackles. One example might be a teenager who finds a Jewish message board and posts, "The Holocaust never happened." The teen may not know or care one way or the other--he just wants a reaction. He wants to piss people off. He is a troll.
There are more subtle trolling techniques as well. One Internet dictionary (www.whatis.com) gives a real example in which somebody posted about "the discovery of an ancient African carving containing a list of prime numbers." The poster listed some of the prime numbers supposedly on the carving, some of which weren't actually primes. People who saw the message, thinking he was serious, responded with corrections. The troll then announced that those who spent their time responding to him had been "hooked."
That suggests how the term got its start. Trolling, to those who don't spend all their time in front of the computer, is a method of fishing where you trail bait through the water from a slow-moving boat hoping to hook an unwary fish. An online troll does much the same.