A US judge has thrown out a lawsuit brought by Elon Musk's social media firm X against a group that had claimed that hate speech had risen on the platform since the tech tycoon took over.
X had accused the Center for Countering Digital Hate (CCDH) of taking "unlawful" steps to access its data.
The US judge dismissed the case and said it was "evident" Mr Musk's X Corp did not like criticism.
X said it planned to appeal.
Imran Ahmed, founder and chief executive of CCDH, celebrated the win, saying Mr Musk had conducted a "loud, hypocritical campaign" of harassment and abuse against his organisation in an attempt to "avoid taking responsibility for his own decisions".
"The courts today have affirmed our fundamental right to research, to speak, to advocate, and to hold accountable social media companies" he said, adding that he hoped the ruling would "embolden" others to "continue and even intensify" similar work.
It is a striking loss for the billionaire, a self-described "free-speech absolutist".
The company, formerly known as Twitter, launched its lawsuit against CCDH in 2023, claiming its researchers had cherry-picked data to create misleading reports about X.
It accused the group of "intentionally and unlawfully" scraping data from X, in violation of its terms of service, in order to produce its research.
It said the non-profit group designed a "scare campaign" to drive away advertisers, and it demanded tens of millions of dollars in damages.
But in his decision Judge Charles Breyer said Mr Musk was "punishing the defendants for their speech".
Judge Breyer said X appeared "far more concerned about CCDH's speech than it is its data collection methods".
He said the company had "brought this case in order to punish CCDH for ... publications that criticised X Corp - and perhaps in order to dissuade others who might wish to engage in such criticism".
Mr Musk purchased the platform in 2022 for $44bn (£34bn) and swiftly embarked on a slew of controversial changes, sharply reducing its workforce with deep cuts to teams in charge of content moderation and other areas.
His own posts have also drawn charges of anti-semitism, a claim he has denied.
