The sudden departure of Twitter executives tasked with content moderation and brand safety has left the company more vulnerable than ever to hate speech.

On Thursday, Twitter’s vice president of trust and safety, Ella Irwin, resigned from the company. Following Irwin’s departure, the company’s head of brand safety and ad quality, A.J. Brown, reportedly left, as did Maie Aiyed, a program manager who worked on brand-safety partnerships.

It’s been just over seven months since Elon Musk closed his $44 billion purchase of Twitter, an investment that has so far been a giant money loser. Musk has dramatically downsized the company’s workforce and rolled back policies that restricted what kinds of content could circulate. In response, numerous brands suspended or decreased their advertising spending, as several civil rights groups have documented.

Twitter, under Musk, is the fourth most-hated brand in the U.S., according to the 2023 Axios Harris reputation rankings.

The controversy surrounding Musk’s control of Twitter continues to build.

This week, Musk said that it’s not against Twitter’s terms of service to misgender trans people on the platform. He said doing so is merely “rude” but not illegal.” LGBTQ+ advocates and researchers dispute his position, claiming it invites bullying of trans people. On Friday, Musk encouraged his 141.8 million followers to watch a video, posted to Twitter, that was deemed transphobic by these groups.

Numerous LGBTQ organizations expressed dismay to NBC News over Musk’s decision, saying the company’s new policies will lead to an uptick in anti-trans hate speech and online abuse.

Although Musk recently hired former NBC Universal global advertising chief Linda Yaccarino to succeed him as CEO, it’s unclear how the new boss will assuage advertisers’ concerns regarding racist, antisemitic, transphobic and homophobic content in light of the recent departures and Musk’s ongoing role as majority owner and technology chief.

Even before the latest high-profile exits, Musk had been reducing the number of workers tasked with safety and content moderation as part of the company’s widespread layoffs. He eliminated the entire artificial intelligence ethics team, which was responsible for ensuring that harmful content wasn’t being algorithmically recommended to users.

Musk, who is also the CEO of Tesla and SpaceX, has recently played down concerns about the prevalence of hate speech on Twitter. He claimed during a Wall Street Journal event that since he took over the company in October, hate speech on the platform has declined, and that Twitter has slashed “spam, scams and bots” by “at least 90%.”

Experts and ad industry insiders told CNBC that there’s no evidence to support those claims. Some say Twitter is actively impeding independent researchers who are attempting to track such metrics.

Twitter didn’t provide a comment for this story.

In a paper published in April that will be presented at the upcoming International Conference on Web and Social Media in Cyprus, researchers from Oregon State, University of Southern California and other institutions showed that hate speech has increased since Musk bought Twitter.

The authors wrote that the accounts known for posts containing hateful content and slurs targeting Blacks, Asians, LGTBQ groups and others increased such tweeting “dramatically following Musk’s takeover” and do not show signs of slowing down. They found that Twitter hasn’t made progress on bots, which have remained as prevalent and active on the social media platform as they were prior to Musk’s tenure.

Musk previously indicated that Twitter’s recommendation algorithms surface less offensive content to people who don’t want to see it.

Keith Burghardt, one of the authors of the paper and a computer scientist at the University of Southern California’s Information Sciences Institute, told CNBC that the deluge of hate speech and other explicit content correlates to the reduction of people working on trust and safety issues and the relaxed content-moderation policies.

Musk also said at the WSJ event that “most advertisers” had come back to Twitter.

Louis Jones, a longtime media and advertising executive who now works at the Brand Safety Institute, said it’s not clear how many advertisers have resumed spending but that “many advertisers remain on pause, as Twitter has limited reach compared to some other platforms.”

Jones said many advertisers are waiting to see how levels of “toxicity” and hate speech on Twitter change as the site appears to slant toward more right-wing users and as the U.S. election season draws near. He said one big challenge for brands is that Musk and Twitter haven’t made clear what they count in their measurements assessing hate speech, spam, scams and bots.

Researchers are calling on the billionaire Twitter owner to provide data to back up his recent claims.

“More data is critical to really understand whether there is a continuous decrease in either hate speech or bots,” Burghardt said. “That again emphasizes the need for greater transparency and for academics to have freely available data.”

The CCDH analyzed a series of tweets from the beginning of 2022 through Feb. 28, 2023. It released a report in March analyzing over 1.7 million tweets collected using a data-scraping tool and Twitter’s search function and discovered that tweets mentioning the grooming narrative have risen 119% since Musk took over.

That refers to “the false and hateful lie” that the LGBTQ+ community grooms children, according to the report. The CCDH report found that a small number of popular Twitter accounts like Libs of TikTok and Gays Against Groomers have been driving the “hateful ‘grooming’ narrative online.”

The Simon Wiesenthal Center, a Jewish human rights group, continues to find antisemitic posts on Twitter. The group recently conducted its 2023 study of digital terrorism and hate on social platforms and graded Twitter a D-, putting it on par with Russia’s VK as the worst in the world for large social networks.

Rabbi Abraham Cooper, associate dean and director of global social action agenda at the center, called on Musk to meet with him to discuss the rise of hate speech on Twitter. He said he has yet to receive a response.

“They need to look at it seriously,” Cooper said. If they don’t, he said, lawmakers are going to be called upon to “do something about it.”

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