Facebook CEO Mark Zuckerberg is once again in damage-control mode after remarks that seemed to suggest Holocaust deniers have a place on the social media platform.

Zuckerberg was describing how the social media company makes decisions about what content to remove; drawing a distinction between inflammatory hate speech that might incite violence in countries like Myanmar and Sri Lanka, and media operations like InfoWars that peddle in conspiracy theories.

“The principles that we have on what we remove from the service are: If it’s going to result in real harm, real physical harm, or if you’re attacking individuals, then that content shouldn’t be on the platform,” Zuckerberg said in an interview with Recode’s Kara Swisher.

Zuckerberg brought up an example that he said hits closer to home.

“I’m Jewish, and there’s a set of people who deny that the Holocaust happened,” Zuckerberg said. “I find that deeply offensive. But at the end of the day, I don’t believe that our platform should take that down because I think there are things that different people get wrong. I don’t think they’re intentionally getting it wrong.”

That comment sparked a firestorm of criticism online, including from Anti-Defamation League CEO Jonathan Greenblatt, who disputed the notion that those who attempt to negate the established facts of the Nazi genocide of European Jews are merely misinformed.

Zuckerberg sent Swisher an email this afternoon, attempting to clarify his earlier remarks, saying he had no intentions of “defending the intent” of people who deny the Holocaust.

“If something is spreading and is rated false by fact checkers, it would lose the vast majority of its distribution in News Feed,” Zuckerberg wrote. “And of course if a post crossed line into advocating for violence or hate against a particular group, it would be removed. These issues are very challenging but I believe that often the best way to fight offensive bad speech is with good speech.”