You really have to go to the newsgroups to see the evolution of the word.
Before 1991, the word almost exclusively meant actual trolls of the D&D / Tolkien / Scandinavian vein. Troll dolls became popular that year, and that kind of diluted the issue a bit.
Then around early 1992, there came a user named Troll on the old alt.flame usergroup that was (for lack of a better word) a troll - more of a proto-troll, as he was on a usergroup dedicated to flaming, so he fit in. But even by their standards he brought the race-baiting, sexism, feigned ignorance, extremist political views, etc. to a new high.
First post July 8, 1992.
He seems to indicate his name comes from being a good insulter, and thus a sort of nasty guy -in other words, a troll.
I believe his name popularized a growing concept and made it the meme it is today.
Eventually it spread out, here's a 1993 post on alt.folklore.urban that still uses quotes around trolling to indicate its status as jargon..
The second post explicitly conflates trolling and fishing.
And the third confirms that trolling at a.f.u. began "1-1.5 years earlier", which syncs with what Wikipedia broadly states about the etymology.
Then Kibology blew up and kind of ran with it, and actually added notes about it to their FAQ, and stabilized it forever.
So trolling when it was just flaming was "nasty thing", then when it became more sophisticated it became "fish baiting."