If by 'rotten apples' you mean someone who speaks their mind but is overly critical of a player, manager, chairman or the club generally then I think we know who most of them are. A forum is a great place for them to air their views. If you watch the Gills you will have heard a lot harsher, agressive criticism around you home or away. I'm probably guilty of looking for the positive in every crappy result or poor performance so it balances out.
Some are just making mischief and wait for someone to bite. KOL and Facebook is the place to go for the angry extremists who don't go to games but rant like they own the club!