In a Tuesday interview with CNN, Mark Zuckerberg defended Facebook's handling of recent scandals and his own leadership of the company. He flatly rejected calls to give up his position as the chairman of Facebook's board and said he had no plans to fire his top deputy, Sheryl Sandberg.

He argued that despite Facebook's recent problems, the site "is a positive force because it gives more people a voice."

It's not surprising that Zuckerberg would defend his own company. But Zuckerberg is wrong: there's no reason to think Facebook is a "positive force" and a lot of reasons to think the opposite.

Facebook makes people lonely and depressed

In a recent University of Pennsylvania study, researchers asked a group of college students to limit their time on Facebook, Instagram (owned by Facebook), and Snapchat to a total of 30 minutes per day. They found the change had a positive effect on their mental health.

"Using less social media than you normally would leads to significant decreases in both depression and loneliness," the researchers said.

That's consistent with past findings. A 2015 study from the University of Houston also found that heavy Facebook use was connected with depression.

"The use of Facebook was negatively associated with overall well-being," two other researchers wrote in 2017.

Facebook has a genocide problem

Last month, The New York Times reported that members of the Myanmar military organized a systematic disinformation campaign to demonize the country's Muslim Rohingya minority group. That campaign helped fuel violent persecution that led to thousands of Rohingya deaths.

The story was similar in Sri Lanka, where Buddhist extremists have carried out a series of extrajudicial killings of Muslims.

"A reconstruction of Sri Lanka’s descent into violence, based on interviews with officials, victims and ordinary users caught up in online anger, found that Facebook’s newsfeed played a central role in nearly every step from rumor to killing," the Times reported.

Of course, Facebook is ubiquitous around the world, so it's not surprising that Facebook plays some role in atrocities all over the world. But there's reason to think Facebook's product design decisions make these kinds of situations worse.

Facebook is obsessed with “engagement”

One of the central values of Facebook's corporate culture is "engagement." Sometimes this is taken to ludicrous levels:

Facebook seems desperate to have users spend as much time on Facebook as possible, and the company seems to have few scruples about how they do it. Spammy notifications are just one example.

Facebook's decision to open its user data to third-party apps—a decision that became intensely controversial after the data was harvested by the Trump-linked political consulting firm Cambridge Analytica—was an effort to increase engagement.

The prominence of partisan and clickbait content in our Facebook Newsfeeds reflects Facebook's obsession with engagement. This kind of content draws people in, even if they often feel dirty about it afterwards. In the US, this has contributed to a bitterly polarized political climate. In countries with weaker political institutions, it has contributed to wide-scale bloodshed.

One defense of Facebook is that the company is just giving users what they want. And that's true—but only in the sense that casinos give heavy gamblers what they want. Facebook peddles the information equivalent of junk food, relying on people's addictive tendencies to maximize consumption. It's a perfectly legal business strategy, but it's not a particularly noble one.

Zuckerberg argues that Facebook is a positive force in the world because it "gives more people a voice." But I'm old enough to remember what the Internet was like before Facebook came along. In 2003, there were lots of ways for people to express themselves online. Facebook didn't invent online discussion. It wasn't the first site for photo or video sharing. If Facebook disappeared from the Internet tomorrow, people would still have plenty of ways to make their voices heard.

What distinguishes Facebook from a lot of other online sites is the company's ruthless, all-consuming focus on growth. Every Internet company wants to grow, of course, but some companies also try to promote other important values. People like to mock Google's "don't be evil" slogan, but the company really has made difficult calls in the past—like pulling out of China over pressure to build a censored search engine.

By contrast, Facebook only seems to care about promoting the continued growth of Facebook. It has tinkered at the margins to try to blunt the platform's worst impacts—like trying to police fake news on the platform. But there's no sign that Zuckerberg is thinking seriously about changing Facebook in fundamental ways that could actually make it a positive force in the world. It certainly doesn't seem like one right now.