Trolling is like obscenity or justice: difficult to define precisely, but we all know when we see it.
There's a distinction to be made between "good" trolling and "bad" trolling. Granted, "good" and "bad" are likely insufficient terms, and probably far too dichotomous. However, you likely get the point.
I'm all for "good" trolling, though there's an art to it. Too much "good" trolling can quickly decompensate into what most would consider "bad" trolling. You have to know when trolling is okay and when to back off. Too much trolling and the trolled begin to rebel.
Some people on here likely consider themselves to be quite clever and perceive themselves to be masterful trolls. In reality, though, they're probably just fucking annoying.
The incessant negative, off-topic commentary (i.e., shitting in threads) and going out of your way to pick on people for little to no reason other than you feel like it's funny are two things I would consider within the domain of "bad" trolling. However, considering this is the Internet, I'm not sure how you'd ever completely rid a place like this of stuff like that.
Being on CR is voluntary and a privilege. If I don't like "bad" trolling, then I'm free to leave. Similarly, the powers that be can exercise their power how they see fit. If someone here with the power to ban doesn't like your trolling - however they decide to conceptualize it - they can ban your ass and that's that. So, my unsolicited advice is to the banned trolls is this: stop trolling, leave, or be better trolls so you won't get banned as much.