Facebook founder and CEO Mark Zuckerberg testifies during a Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee joint hearing about Facebook on Capitol Hill in Washington, DC, April 10, 2018.

Republican Senator John Kennedy of Louisiana confronted Facebook CEO Mark Zuckerberg about the transparency of the social media company's policies during a joint hearing of the Senate Judiciary and Commerce committees on Tuesday.

"Here's what everyone's been trying to tell you today — and I say it gently — your user agreement sucks," Kennedy said. "The purpose of a user agreement is to cover Facebook's rear end, not inform users of their rights."

Zuckerberg appeared momentarily amused, but the comment hits at an issue central to Facebook's data scandal: transparency.

Critics argue Facebook users aren't well informed about Facebook's plans for their data. Kennedy believes this partly because those plans are laid out in a long and complicated user agreement. Even Zuckerberg later admitted most users probably don't read it.

"I would imagine probably most people do not read the whole thing," Zuckerberg said. "But everyone has the opportunity to and consents to it."

And just in case Zuckerberg wasn't entirely clear on Kennedy's point, the Senator left him with some colorful advice.

"I'm going to suggest you go home and rewrite it, and tell your $1,200 dollar and hour lawyer…you want it written in English not Swahili, so the average American user can understand," Kennedy said.

Facebook is facing questions following reports that research firm Cambridge Analytica improperly gained access to the personal data of as many as 87 million Facebook users.

Zuckerberg has faced tough questions on user privacy, foreign meddling on the site and abuse of social media tools.

He's scheduled to testify before the House Energy and Commerce Committee Wednesday. His prepared remarks for that hearing were released Monday.