As described in this article, the explanation seems to be that the topic has grown too contentious (?):

Some workers have suggested using the word “onion” to refer to unions to circumvent the new rule. 

Huffpo on the many dangers female streamers face, including finding horrifying subreddits dedicated to them:

Even the takedowns Blaire pays for are limited in scope. Reddit and other platforms will generally comply with DMCA notices demanding the removal of copyrighted material, explained Morrison, the attorney, so content that’s taken from Blaire’s livestream and reposted elsewhere online usually ends up coming down in the face of legal threats. But getting these platforms to take action on the grounds of sexual harassment — and to remove entire channels or subreddits for consistently abusive behavior — is much more difficult. 

After HuffPost reached out for comment last week, Reddit finally banned the subreddit harassing Blaire, citing “excessive copyright removals.”

“Our site-wide policies prohibit content or behavior that threatens, harasses, or bullies individuals or groups of people. Users and subreddits that engage in such behavior will be banned,” Reddit said in a statement to HuffPost. “Additionally, in accordance with Reddit’s User Agreement, we respond to valid DMCA takedown requests for cases of infringing or copyright materials and will action any users or communities in appropriate circumstances.” 

A new subreddit was created almost immediately and remains active.

Cecilia D'Anastasio for Wired:

traders on the chaotic and obscene subreddit WallStreetBets helped push GameStop’s stock price up from $20 on January 11 to $73 after traditional analysts deemed the stock a clunker.

..

As a collective, the subreddit has previously amassed enough bodies and enough funds to drive unlikely rallies in the stocks of companies like Lumber Liquidators and Plug Power. “It was a meme stock that really blew up,” said WallStreetBets moderator Bawse1. “The massive short contributed more toward the meme stock.” GameStop seemed so utterly doomed that the current situation was actually sort of funny to the subreddit’s denizens. 

...

On Friday, Left set up a second Citron Research Twitter handle, claiming that several people had attempted to hack the main account, potentially in an attempt to disrupt his livestream. In a note tweeted from that backup account, Left wrote that “an angry mob who owns this stock has spent the last 48 hours committing multiple crimes,” alleging that the same group harassed “minor children” as well. He says in his YouTube video that someone ordered pizzas to his house and signed him up for Tinder.

WallStreetBets moderator Bawse1 says that he doesn’t know if those things happened, “and if they did, it’s not something we condone or promoted.”

Basically:

The stock market is just fantastically weird right now. It's such a huge story, and very reminiscent of the political system being overrun by memelords in 2016, as whatever you'd call the establishment just looked on in confusion / terror / horror https://t.co/iLOeDBDlAi

— Tom Gara (@tomgara) January 22, 2021

The 2016 parallels to the stock market being memelorded are everywhere. You'd assume there are guardrails against this? No. Grownups will eventually win out, either with brute force institutional power or tactical smarts? No. This can just like, happen? Yep.

— Tom Gara (@tomgara) January 22, 2021

I wouldn't worry too much about this Gamestop 70% stock surge thing, history suggests that aggrieved gamers co-ordinating on Reddit are unlikely to have any lasting impact https://t.co/5iAoqgXrYF

— Tom Gara (@tomgara) January 22, 2021

A current writer for the New Yorker:

my mom, being a proud and loving mother who likes to send stories about me to her friends, has searched my name online regularly for years, despite my protests. She recently alerted me to the fact that details about [a criminal case involving my parents from several years earlier] had been added to my Wikipedia page. A post was circulating on Tumblr about it, and on Twitter . . . and by Friday . . . people were posting about how my parents were human traffickers. The vibe was that this was some sort of wild, ironic gotcha. Here I was, a writer who had made a whole thing of being concerned with public morality, who had managed to project some aura of decency and transparency, and my parents were—as far as anyone who’d come across this juicy nugget was concerned—international criminals who had built their lives off exploiting other people, off their suffering and pain.

Over the following week it was made clear to me that more and more people were discussing this situation as a reputational time bomb that was going to be especially exciting to see go off.

Insider:

Enlisting the help of attorneys and a cyber investigation company, she and her family explored every avenue — from analyzing her phone records to finding the sources of anonymous DMs and Reddit posts — ultimately tracing much of the false information back to two people who had been stalking her fiancé and had expressed a vested interest in [her celebrity fiancee] becoming single.

The process, Cooper says, was "insane" and grueling, and she struggled to make sense of the bizarre vendetta against her.

"It's really hard to prove you didn't do something," she said. "And I just didn't know why someone had it out for me like this."

...

One subreddit contributor wrote a post titled "This sub owes Jenna Cooper (and others) a huge apology," in which they recapped the online forum's role in spreading misinformation and implored Redditors to do better in the future.

"This isn't even the first time this sub has publicly crucified someone over something that turned out to be fake," the post reads.

Mel Magazine:

“My dad used to troll Saved by the Bell message boards in the 1990s

...

“But AITA is getting extremely heavily moderated,” she says. “I actually don’t troll there very much anymore. Everyone is looking out for fake posts.” She lists a few common tells for fabricated situations: “One is ‘My husband is obsessed with [insert niche thing here].’ These posts got really popular lately, so they’re pretty much always fake.”

...

So how does something like the Harry Potter wedding gambit succeed while other shitposts are outed as bogus? It’s about the exact points of plausibility and discord. The Hogwarts house bride plays well “because, first of all, people like that actually do exist, and second of all, Harry Potter isn’t something Reddit hates, if anything it’s just highly polarizing,” CHH explains — therefore, commenters will engage with it.

...

Reddit banned her — a few of her accounts in 2019, then her actual IP or device (she’s not sure which) in 2020. She has a strategy to get around the block, which she declined to share for obvious reasons, but it’s a method that keeps her from practicing the skill of “Long Game Trolling,” where she creates deep posting histories for years under a given screenname to gain trust and legitimacy.

The worst part of being a journalist is being even semi in the public eye. Even dealing with a fraction of what actual public figures go through has been shocking and horrible. It’s completely changed how I live my life and has severely affected my mental health over the past yr

— Taylor Lorenz (@TaylorLorenz) February 1, 2020

Like... no one online knows anything about my actual life. If you think you know me because you follow me online, you know maybe 5% of my life. I don’t post about what’s actually happening or who I actually care abt b/c of these psychos on Reddit and FB groups. They are truly ill

— Taylor Lorenz (@TaylorLorenz) February 1, 2020

"Earlier in the day, a legislative committee had voted along party lines that no action be taken against Republican Robert Fisher"

DD:

2) The r/findbostonbombers moderators | The FBI’s most mettlesome

Boston was in lockdown. Three people had been killed and more than 260 injured in an attack near the finish line of the Boston Marathon. A manhunt unlike anything Americans had seen since Sept. 11, 2011 was underway. On Reddit, thousands of users were poring over photos and videos of the April 15 attacks—information they published to r/findbostonbombers.

Two days after the attack, using information gathered on Reddit, the New York Post ran a photo of two men it alleged were persons of interest in the case. The newspaper has a circulation of more than 500,000 and its website is one of the most visited in the U.S.. The newspaper, and Reddit’s sleuths, were wrong. The men had nothing to do with the bombing. After that misfire, redditors found a second top suspect: Sunil Tripathi, a Brown University student who had been missing since March. He, likewise, was completely innocent.

In the end, r/findbostobombers was shut down. And Reddit issued an apology to the Tripathi family. “The Reddit staff and the millions of people on reddit around the world deeply regret that this happened,” general manager Erik Martin wrote.

DD:

I first heard about Reddit’s Century Club in September, after a mysterious persona called UpMan made Internet history.

In just 11 days, the redditor collected 100,000 points of comment karma—otherwise meaningless Internet points that give prolific Reddit users clout. Karma is Reddit’s virtual voting system. It rewards users for providing the community with content and commentary.

UpMan had a ton of it—and he got it faster than anyone, ever.

1. Optimizing bots caught gaming Reddit. (There's an entire subreddit dedicated to analyzing Reddit.)

2. "Richard B. Riddick, the shaven-headed silver-eyed antihero of Pitch Black and its sequels, is an exemplar of that hoary old SF trope - the competent man."

3.  "Stalin's Rope Roads" - - a real life town that feels like a location in Syberia.