(Washington) Social media platform X, formerly known as Twitter, is threatening to sue a group of independent researchers who have documented a spike in hate speech on the site since it was taken over by Elon Musk last year.

A lawyer representing the social media site wrote to the non-governmental organization Center for Countering Digital Hate on July 20 threatening legal action over its research on hate speech and moderation of content.

The attorney alleges that the nonprofit’s research posts appear intended to “harm Twitter’s business by driving advertisers away from the platform with inflammatory allegations.”

Elon Musk, who calls himself a “free speech absolutist”, welcomed back white supremacists and election deniers to “his” platform, which he renamed X earlier this month. But the billionaire has sometimes been sensitive to critical speeches directed against him or his companies.

The “Centre to Counter Online Hate” is a non-profit organization (nonprofit) with offices in the United States and the United Kingdom. The center regularly publishes reports on hate speech, extremism or harmful behavior on social media platforms like X, TikTok or Facebook.

The nonprofit has published several reports that fundamentally criticize Elon Musk’s leadership, documenting an increase since his acquisition in hate speech targeting LGBTQ communities as well as climate misinformation. X’s lawyer’s letter cited a specific report from June that the platform had failed to remove neo-Nazi and anti-LGBTQ content from verified users that violated the platform’s rules.

Imran Ahmed, founder and CEO of the nonprofit, told The Associated Press on Monday that the center had never seen such a response from a tech company. He argues that typically companies targeted by criticism from the center respond by defending their work or promising to fix any problems identified.

Mr. Ahmed therefore fears that X’s reaction could have a chilling effect on other researchers who were not studying the platform. He also worries that other industries will take notice of the strategy.

Messages left for Me Spiro and X were not immediately returned on Monday.

This isn’t the first time Elon Musk has hit back at critics. Last year, he suspended the accounts of several journalists who were covering his Twitter takeover. Another user has been permanently banned for using publicly available flight data to track the billionaire’s private plane. Mr. Musk also threatened to sue him.

Twitter’s new owner initially promised he would allow any speech on his platform that wasn’t illegal — even his “worst criticisms, because that’s what free speech means,” he wrote in a message on Twitter last year.