Angela Lang/CNET

Internet platforms like Google can censor content, according to a ruling Wednesday from a federal appeals court in California.

The unanimous decision came from the Ninth US Circuit Court of Appeals in San Francisco. In a suit, Prager University said that its videos featuring conservative viewpoints were flagged and demonetized, and that Youtube threatened "conservative viewpoints and perspectives on public issues."

In the opinion, circuit judge M. Margaret McKeown wrote, "Despite YouTube's ubiquity and its role as a public facing platform, it remains a private forum, not a public forum subject to judicial scrutiny under the First Amendment."

The ruling drew in part on other court cases that have "uniformly concluded" that internet platforms, including Facebook and Twitter, that "open their property to user-generated content do not become state actors."

Google, which owns YouTube, didn't immediately respond to a request for comment.

"Of course this ruling is disappointing, but we won't stop fighting and spreading public awareness of Big Tech's censorship of conservative ideas," PragerU CMO Craig Strazzeri said in a statement.