Well, the way I see it, I can have one brief thread giving them attention and then everyone (hopefully) stops, or we just keep endlessly feeding them with no end in sight. Which option gives them more attention in the long run?
"They" will feed on your flesh and drink your blood. Threads like this are like a playground for, ahem, us.
Whenever the subject is interesting though, there will be valuable contribution. Learn to zone out the useless cruft on useful threads, and just plain don't read the obviously troll threads, nobody forces you to do that.
Besides, whenever there is friendship, there is also a trolling camaraderie which does not mean bad blood. It just takes time to understand the relationship dynamics.
You know, it's a situation like, if your crotch is hurting, stop pulling your pubic hair so hard at all. You're doing it wrong.