In a series of tweets late Friday night, Elon Musk, the CEO of X Corp, expressed his frustration and anger towards large advertisers and Media Matters, a prominent media watchdog group. This outburst came after several major brands decided to halt their ad spending on X, the social media platform owned and operated by Musk as CTO.

The trigger for this backlash was a report published by Media Matters for America (MMFA) that revealed mainstream brands' advertisements running alongside user posts promoting pro-Nazi and other hateful views on X, previously known as Twitter. The revelation raised concerns about brand safety and association with controversial content.

Additionally, Musk himself faced backlash after posting tweets that were characterized as "abhorrent promotion of antisemitic and racist hate" by the White House. These tweets further contributed to the decision of advertisers, including Apple, Comcast/NBC Universal, Disney, IBM, Lions Gate, Paramount Global, and Warner Bros. Discovery, to temporarily suspend their ad spending on the platform.

Responding to the situation, Musk wrote, "The split second court opens on Monday, X Corp will be filing a thermonuclear lawsuit against Media Matters and ALL those who colluded in this fraudulent attack on our company." He went on to mention potential legal action against the board, donors, and network associated with Media Matters, vowing that the discovery and depositions in the lawsuit would be "glorious to behold."

As news of the suspended ad campaigns emerged, Musk also promoted a paid, ad-free subscription version of X, emphasizing that it would not have ads in users' timelines. He cryptically referred to "the greatest oppressors of your right to free speech," without specifying the particular large advertisers he believed were involved.

Joe Benarroch, a spokesperson for X, dismissed Media Matters' findings, accusing them of misrepresenting the user experience on the platform. Benarroch stated that Media Matters had created an alternate X account, deliberately followed sensitive accounts, and curated posts to misinform advertisers about the placement of their ads. He argued that such contrived experiences could be created on any social media platform.

It's worth noting that other social media platforms, including Facebook, Reddit, and TikTok, also grapple with the challenge of brand safety and moderating hateful and false content.

The controversy surrounding Musk's tweets has drawn attention to his personal amplification of bigoted viewpoints, coinciding with the suspension of major ad campaigns. Musk has supported posts that falsely claim Jewish people perpetuate "dialectical hatred" against white people, prompting intense criticism from various quarters, including the White House. In response, the White House condemned Musk's behavior as an "abhorrent promotion of antisemitic and racist hate," which they said contradicts American values.

Later on Friday, Musk announced a new policy for X, stating clearly that "clear calls for extreme violence" are against their terms of service and will lead to suspensions. This declaration was welcomed by the CEO of the Anti-Defamation League (ADL), Jonathan Greenblatt. Musk has had a contentious relationship with the ADL, a Jewish-led organization that combats hate speech and discrimination, and he had previously threatened legal action against them.

While it remains unclear whether X Corp. will actually file a lawsuit against Media Matters, the tension between Musk's company and the media watchdog group continues to escalate. X, based in San Francisco, and Media Matters, based in Washington, D.C., exist in different jurisdictions, adding further complexity to any potential legal action.

In response to Musk's threats, Media Matters President Angelo Carusone issued a defiant statement, asserting that if sued, they would emerge victorious, highlighting that Musk himself had confirmed the accuracy of their report.

As the controversy unfolds, it raises important questions about brand safety, responsible content moderation, and the limits of free speech in the digital realm.

CNBC's Jonathan Vanian contributed reporting to this article.