Facebook, Twitter and Alphabet-owned YouTube went before Congress again Tuesday to address claims of conservative bias, and at least one Democratic representative thought it was ridiculous.

“So let me just ask some very basic questions so the American public understands what a dumb hearing this entire hearing is,” said Ted Lieu, a Democratic representative from California. He then asked a series of questions that led company representatives to acknowledge that they were from private companies.

Lieu’s point was that the companies’ responses don’t matter since Facebook, Twitter and Alphabet are private, profit-seeking companies and not public entities.

“I don’t even know why we’re having this hearing,” Lieu said. “Your duty is to your shareholders. Not the members of this committee.”

Lieu also said, “It’s stupid because there’s this thing called the First Amendment,” Lieu said. “We can’t regulate content.”

The tech giants have faced questions of conservative censorship for months, and have repeatedly insisted their platforms are neutral, their rules are clear or getting clearer, and their companies believe in free expression provided it doesn’t constitute abuse.

Later in the hearing, Rep. John Rutherford, R-Fla., responded to Lieu by defending the validity of the holding the session:

“Potential censorship of free speech I think goes to the core of our country’s freedoms and to suggest that because we’re not talking about some items that are in the news, that somehow this is ‘ridiculous,’ when considered in light of the balance between free speech and public safety … that’s why this hearing I think is so vitally important.”

The controversy over content regulations peaked earlier this year when conservative bloggers Diamond and Silk began noticing dwindling audiences on Facebook, and claimed conservative censorship. The two women were invited to appear before the same House Judiciary Committee in April — where Lieu made similar exasperated comments.

In a recent study, researchers have found no evidence of company bias on Facebook, and all three companies have denied allegations of political bias in their policies.

Last week, a Facebook news conference sparked a debate over whether Facebook should ban the page of InfoWars, which is known for spreading conspiracy theories — leading journalists and governmental officials from both sides of the aisle to call for clearer guidelines.

The platform said it would not because it does not “take down false news,” although it will demote content deemed false. Neither YouTube or Twitter have blocked InfoWars from their platforms either.

“The only thing worse than watching an Alex Jones video is the government trying to tell Google not to do it — to prevent people form watching the Alex Jones video,” Lieu said. “We can’t even do it if we tried.”

—CNBC’s Jillian D’Onfro contributed to this report.