Facebook’s existential crisis arrived with a vengeance this week. But Mark Zuckerberg didn’t want to talk about it much.

Yes, as he took the stage Tuesday in San Jose for his keynote address at a Facebook conference, he nodded to what had happened just two days before: A cold-blooded killing posted for millions to see, with live-streamed commentary from the killer soon after.

“Our hearts go out to the family and friends of the victim in Cleveland,” Zuckerberg said. “We’ll do all we can to prevent tragedies like this from happening.”

But then Facebook’s founder and chairman dived right into an extended discussion of the next Facebook frontier — augmented reality, which integrates digital information with the user’s experience in real time.

His mention of the killing, while seemingly sincere, still felt like a kiss-off.

But it’s not surprising. Denial is, far too often, the Facebook way.

Remember just after the presidential election when Zuckerberg shrugged off the importance of the hyperpartisan lies in the form of news stories — such as Pope Francis supposedly endorsing Donald Trump?

“Personally, I think the idea that fake news on Facebook, which is a very small amount of the content, influenced the election in any way — I think is a pretty crazy idea,” he said.

In time, he changed his mind about that, and Facebook, to its credit, has made some significant moves to flag, limit and remove financial incentives for lies and misinformation that spread like a disastrous oil spill during the campaign.

But Facebook still hasn’t come to terms with what it really is — a media company where people get their news and which, especially because of the year-old Facebook Live, generates news content. Since it began, rape, a horrible attack on a disabled person and more than one suicide has been live-streamed.

“The crux of this is what is Facebook’s true nature: a technology that enables anyone to publish anything? Or a self-regulating media company with enforced standards?” Emily Bell, director of the Tow Center for digital journalism at Columbia University, told me Monday evening.

Facebook’s answer became clear Tuesday morning.

With its nearly 2 billion monthly active users and more than $10 billion in annual profits, Facebook is better at making money and capturing eyeballs than at owning its equally huge power and responsibilities.

But there are, of course, business reasons not to accept that. As soon as Facebook acknowledges that it is a publisher and not a platform, it may open itself up to lawsuits that could cut into profits fast.

And its Facebook Live has been a force for good, too. Last year, Diamond Reynolds live-streamed the police shooting in Minnesota of her boyfriend, Philando Castile. It was important piece of bearing witness, made poignant by the presence of Reynolds’ tiny daughter.

At this crucial moment, Facebook’s language often sounds clueless, with its combination of stilted corporate euphemism and childlike wonder about “community” and “sharing.”

Following the Cleveland slaying, which remained on the site for hours, a Facebook statement put it like this: “This is a horrific crime and we do not allow this kind of content on Facebook.” Later, a Facebook vice president made a seemingly more thoughtful effort to describe the ways the company would use artificial intelligence and a better “reporting flow” to address the problem.

But none of this was specific enough, or serious enough. Nor did Zuckerberg’s brief mention help.

Facebook is immensely and increasingly profitable — it made more than $10 billion last year, up dramatically from 2015. More than four of every five dollars comes from mobile ads, which makes video a more and more essential to corporate success.

But this can’t go on forever.

Bell summed it up: “If Facebook is really interested in the unbiased nature of discourse it would know that totally unmoderated systems favor the authoritarian bully, and suppress free speech rather than enable it. Ask Twitter.”

An innocent man and his killer — who committed suicide Tuesday — are dead. But that can’t be the end of the story.

Margaret Sullivan is The Washington Post’s media columnist. Previously, she was The New York Times public editor, and the chief editor of The Buffalo News, her hometown paper.