Civil rights leaders have criticised Mark Zuckerberg’s decision to take no action against a Facebook post from Donald Trump appearing to threaten to start shooting “looters”, after a Monday night meeting with the company’s executives ended in acrimony. “We are disappointed and stunned by Mark’s incomprehensible explanations for allowing the Trump posts to remain up,” Vanita Gupta, Sherrilyn Ifill and Rashad Robison said in a statement. “He did not demonstrate understanding of historic or modern-day voter suppression and he refuses to acknowledge how Facebook is facilitating Trump’s call for violence against protesters. “Mark is setting a very dangerous precedent for other voices who would say similar harmful things on Facebook.” The three activist leaders – the heads of the Leadership Conference on Civil and Human Rights, the NAACP Legal Defense and Educational Fund, and Color of Change – met Zuckerberg, the CEO of Facebook, and its chief operating officer, Sheryl Sandberg, on Monday night. They discussed Trump’s Thursday night post, which urged the military to intervene in Minneapolis with the words “when the looting starts, the shooting starts”. The message, originally sent by Trump as a tweet before being cross-posted to Facebook, was restricted on Twitter after the platform decided it broke rules about glorifying violence. On Facebook, Zuckerberg personally intervened to leave the message up, arguing that the company has a policy to allow warnings of the use of force by state actors. Zuckerberg’s decision led to a “virtual walkout“ of Facebook staff on Monday, with hundreds of employees downing tools in protest. A number of Facebook employees publicly expressed their dissent on rival social networks such as Twitter, and were quickly supported by senior managers at the company. At least one employee has quit over the decision. Timothy J Aveni, a software engineer who worked on misinformation, said on Facebook that he had resigned on Monday. “Mark told us that he would draw the line at speech that calls for violence,” Aveni wrote. “He showed us on Friday that was a lie ... Facebook, complicit in the propagation of weaponized hatred, is on the wrong side of history.” A Facebook spokesperson told the Guardian: “We recognise the pain many of our people are feeling right now, especially our black community. We encourage employees to speak openly when they disagree with leadership.” The company would not require walkout participants to take paid time off, Facebook said. On Monday night, fresh detail about those internal discussions emerged, after the Verge obtained recordings of Zuckerberg speaking at an internal meeting on Friday night. “How to handle this post from the president has been very tough,” said Zuckerberg. “It’s been something that I’ve been struggling with basically all day, ever since I woke up … This has been personally pretty wrenching for me. “My first reaction [to Trump’s post] was just disgust,” he added. “This is not how I think we want our leaders to show up during this time. This is a moment that calls for unity and calmness and empathy for people who are struggling.” Zuckerberg also told employees Facebook would review the policies that allowed Trump’s post to stay up. “There is a real question coming out of this, which is whether we want to evolve our policy around the discussion of state use of force. Over the coming days, as the National Guard is now deployed, probably the largest one that I would worry about would be excessive use of police or military force. I think there’s a good argument that there should be more bounds around the discussion around that.” The Facebook walkout was followed by sanctioned events at other technology companies. A number of YouTube executives, including the company’s chief business officer and its global head of music, told their teams they could take Tuesday off to participate in the protests, according to the Information. On Tuesday morning, Spotify followed suit, encouraging employees to join the day of action “by taking time to reflect and educate themselves”. The decision on whether to allow Trump’s posts to remain on Facebook could be one of the final major calls made solely by Zuckerberg. The company recently confirmed the creation of an independent Oversight Board of academics, politicians and former journalists from around the world who will act as as a “supreme court” deciding what content should be allowed on Facebook, while providing guidance on policy. Members of the Oversight Board met on Tuesday afternoon and discussed the issue but the organisation is reluctant to start wading in to debates before it is up-and-running. It is due to be fully functional by the autumn - towards the end of the current US presidential election campaign. Members declined to give any detail what was discussed on Tuesday, although a spokesperson for the Oversight Board suggested Trump’s posts are the sort of issue they will rule on in the future: “There are many significant issues relating to online content that we recognise people want the board to consider. We’re working hard to set the board up to begin operating later this year so it can start considering cases referred by users and Facebook. We will make decisions without regard to Facebook’s economic, political or reputational interests, in a fair, transparent and politically neutral manner.” Twitter’s decision to restrict the Trump tweet – which was followed by a Trump executive order aimed at reducing the platform’s protections against civil claims – won the backing of the European commission. The EU executive branch’s vice-president, Věra Jourová, said in her response to the dispute that politicians should answer “criticism with facts, not with threats and attacks”. “I support Twitter in their efforts to develop and implement a transparent, clear and consistent moderation policy,” Jourová said. “This is not about censorship. This is about flagging verifiably false or misleading information that may cause public harm, linking to reliable information, or flagging content violating their policies.”