For more than 15 years I spent time, almost every day, on a small forum for alumni of my undergraduate institution. There were a small number of very regular posters who would participate every day (maybe 30-50+), another group of less-often posters (maybe 100+) who might participate a time or two a week, and then a very large number of people who might pop in a couple of times a year.
There are (were) threads that had been going for years. Certain posters would, like clockwork, start a "Football season is here" thread year after year (made up example). There was a culture.
It was a really nice community, many people had met in person, most hadn't, all had some shared experiences, it was civil, and for many years the poster base was very consistent. I've known some of these guys for literally 15 years now.
About 2 years ago, a new member joined. He is civil, he's not a shitposter, nothing too objectionable on his own. What he is though, is completely fucking obsessive. He's always the first to comment on a new post. He responds to most comments as if they were addressed to him personally. He gets his own point of view--multiple times--out there in every single discussion.
Again, he's not rude, he's not a troll, and he's not insane (he does have an annoying tendency to humblebrag flex), he's just a super poster times ten...times a hundred.
And he has completely destroyed the community. One guy.
I got tired of seeing his name so much, and I found I've stopped reading the forum more than once a week or so. I haven't posted in a couple of months. A good IRL friend of mine commented the same thing to me out of the blue. The "familiar" names that have been ever present for many years are dropping off the forum one by one. I noticed today that a December Christmas thread that reactivated every December since like 2010 hasn't been posted in since last year.
As the longtime regulars are disappearing, new names are becoming regulars, and the tenor of the place is changing.
I guess I'm just amazed that one guy--literally one guy--was able to destroy a community than had been around for decades.
It's not really a case of gatekeeping--he is an alumnus of the school. It's not like the moderators have a rule: "Don't post too often." I don't know what could have stopped this guy. It's just crazy.
I don't disagree that one user can kill a community, because it's definitely possible. I just think you discount a lot of the other factors. Communities often build on shared experiences. Whether that's going to school, learning, playing video games, politics, etc... Yet over time, people grow and change themselves which impacts any community.
I've been a part of a lot of niche communities on the internet and all of them change. I could look back and try to pin the blame on one user if I wanted but that would be disingenuous. Sure, the one mod started over moderating, the one user started spamming whatever he cared about, what used to be civil discourse changed to memes, whatever. There's always disruption and sometimes communities just die out on their own because what used to unify people no longer mattered.
I mean, take this community for example. I wasn't here from the beginning but if I understand it, it's about video games that then became political after gamergate. That right off the bat lets me know a few things. The original demographics are going to be teenagers, likely single, in school. The demographics then shift to young adult, serious relationships, marriage, career. The demographics right now lead to an enviable collapse of the community because most quality people are going to dip out of discussing video games and gender wars before they hit 30yo to focus on more important things. If they come on from time-to-time they aren't going to want to see whining and complaining and blackpills since their life is going good, they'll want to see more positivity. Over time the community will simply emcumbus mostly those who are bitter and upset about their current situation in life and even then posting becomes a bore. You can only discuss the same things over and over again before you've discussed them to death. I mean take gaming on its own, skip the politics. The whole gambling style of gaming has mostly killed gaming. Big name gaming companies are making mobile games to sell skins for $20 to some rich Asians. Gameplay is something that hasn't been innovated since the 2000s. What's there left to discuss except how shit most games are these days.
Anyway, I'm rambling. The point I'm trying to make is all good things come to an end, including internet communities. It's not usually 1 guy that killed it. He may have been the catalyst but it was already dying by then, otherwise it would have likely been robust enough to survive one subverter. You can draw the same parralel to western society if you'd like as well.
This community only came into being after GG; it was always political. KotakuInAction had been around already but it was primarily about criticizing Kotaku ... because Kotaku politicizes everything needlessly.
It was the leftists in the original KotakuInAction that subverted it into, "what does this have to do with video games?" They drove everyone into KiA2 for non-censored discussions, and then the general atmosphere of Reddit pushed more people out.
It was always about the politicization of video games.
That's a pretty niche topic that's going to get old pretty fast though. At first it's about proving it's happening but then it becomes too hard to deny, then it becomes about figuring out why. Once you have that down, it becomes what can you do about it. Then you've tackled everything and there's not much more to discuss.