Mosseri, who has run Facebook-owned Instagram since October of last year, initially responded to a tweet from New York Times opinion writer Charlie Warzel, who shared an article he wrote analyzing Facebook's inclusion of the far right news outlet in its news product unveiled on Friday. Breitbart, which was previously run by President Donald Trump's former advisor Steve Bannon, has been accused of defending white nationalists, both in various news articles and on Twitter. This is in part why Mosseri was defending Breitbart's inclusion on Facebook News Tab.
Mosseri wrote that Warzel should consider if he'd "really want [a] platform as big as Facebook embracing a political ideology?" He also asked why there seems to be "such a different reaction" to Breitbart being a partner with Apple's subscription news product.
In later responses, Mosseri clarified that he was not defending Breitbart and said he doesn't "even want Breitbart to be part of Facebook News."
"I simply asked if it was more important to get your way than to be default open to speech?" Mosseri tweeted. "The stakes are so high it just might be, but I believe it's worth asking the question."
A Facebook spokesperson said Breitbart is not among the publishers the company will pay to host content in the Facebook News Tab. The spokesperson said Breitbart is "eligible to appear in the tab because their current content on Facebook meets the guidelines."
In a statement, a Breitbart spokesperson said, "Breitbart News routinely ranks among the top five news sites in the U.S. according to Amazon-owned Alexa, we are the #14 most-engaged Facebook publisher in the world, and Breitbart News also recently was approved by AT&T for its AppNexus/Xandr ad platform--it makes sense that Breitbart News Network is included in the Facebook News Tab."
Breitbart also flatly rejected the accusation that it is a proponent of white nationalism.
"It is absurd to suggest Breitbart promotes or defends white nationalism, especially as our founders and leadership team are Jewish; a New York Times Magazine profile praised us for our record of promoting women and minorities; and a Harvard/MIT study concluded that 'Breitbart is not the alt-right,'" the organization said in a statement to CNBC.
Facebook's News Tab represents a different approach for the company toward the media industry than in the past. Through the new product, Facebook will pay about 200 publishers included in the program to license their product. CNBC parent company NBCUniversal is among the publishers taking part. Facebook said the product will be curated by an independent team of journalists to limit its own influence.
But the hands-off approach to the news curation clearly hasn't insulated Facebook from criticism about what will be included in the feature. As Mosseri noted, Apple did not seem to receive as much criticism for including Breitbart in its own news product. But the additional skepticism of Facebook likely stems from its history of altering traffic flows to news websites and its role in allowing political data firm Cambridge Analytica spread pro-Trump content on its platform leading up to the 2016 U.S. presidential election.
Facebook introduced the news feature on the same week that CEO Mark Zuckerberg testified before congress on the company's cryptocurrency plans and was blasted for the company's record on civil rights and diversity. A joint antitrust probe into Facebook announced that 47 states and territories had now joined the cause, adding to investigations by the Federal Trade Commission, the House Judiciary Committee and reportedly from the Department of Justice, according to Reuters.
In response to Mosseri's initial comment, Warzel replied, 'no snark but.. i...think you're making an argument that Facebook is maybe too big?"