As Common Dreams reported, news of the dinner set off a firestorm of criticism from progressives who found both the meeting and the secrecy indicative of what Sen.
Twitter, Facebook and Google have all laid out their stance on political advertising ahead of the United Kingdom elections - with Twitter banning ads by politicians while Google has said that they will ban ads that make "demonstrably false claims that could significantly undermine participation or trust in an electoral or democratic process".
The "free expression" Zuckerberg was speaking about specifically referred to political speech.
Its rival, Twitter, has banned political advertising on its platform, while Google has said it will no longer allow voters to be targeted by advertisers based on their political affiliation.
Although Facebook took down the advert, this forms part of a broader discussion around political advertisements.
The BBC asked the Tories to take the ad down, only to be rebuffed. It adheres to an worldwide standard for fact-checking: The global Fact Checking Network, run by Poynter.
At another point in the interview, Zuckerberg reiterated his opinion that Facebook shouldn't be in the business of fact-checking ads. "Just as critically, by limiting political speech we would leave people less informed about what their elected officials are saying and leave politicians less accountable for their words".
In October, Facebook CEO Mark Zuckerberg was in Washington, DC, for a grilling by lawmakers.
The framing of King's question-that Zuckerberg, not Trump, was the one at the dinner being lobbied-was notable to Financial Times reporter Kadhim Shubber.
The details of the dinner in October remain elusive, but some new information came out of an interview with Zuckerberg on "CBS This Morning" on Monday.
"When Mark and I talk about these issues together, I also have the lens of being an educator and pediatrician that's worked deeply with families and individuals in all types of communities", Chan said.
"No. I think some of the stuff people talk about or think gets discussed in these discussions are not really how that works", he said.
To be clear, we're talking a private dinner between the President of the United States - the most public role of all public roles in American life - and the CEO of one of the world's most powerful companies.
In the interview, Zuckerberg echoed previous statements he'd made about the choice.
"What I believe is that in a democracy, it's really important that people can see for themselves what politicians are saying so that they can make their own judgments", Zuckerberg said.