Civility has become a cult.
Mods on modern websites (including Reddit and Lemmy.world) are forced to maintain courtly behavior instead of deciding who's the asshole. They will protect any cautious troll who can politely phrase 'you're subhuman and also secretly agree with me' but jump on the obvious reasonable response: "Fuck off." Even when that curt dismissal is followed by an explanation of how a comment was dishonest and manipulative, you said the no-no word, so only you get the boot.
And that boot will tend to be as heavy as possible, sometimes instantly permanent, because god forbid anyone learn anything. You keep permanently banning these trolls, when they can get a new account in minutes, and they keep coming back within minutes? Wow, it's almost like you've given them no reason whatsoever to stick out their ban and keep that username. Spritzing them in the face with a three-day time-out works better. This is basic Skinnerian conditioning - immediate reliable feedback is internalized and shapes future behavior.
I think it's a bit strange that we call everyone a troll these days though. Since when is it trolling to just state your opinion? Trolling was supposed to be when someone intentionally posts something to upset someone else.
It's very hard to actually know the difference unless it's a stupid poster who does it over and over again.