A fun thing about content moderation—the practice of social-media platforms deciding what we can and cannot say in some of the world’s most important online spaces—is that almost everyone thinks that it’s broken, albeit in different ways. Almost everyone also thinks that if you just put them in charge, they would fix things. When you’re the world’s richest man, you can actually give it a shot. And so, Elon Musk is buying Twitter, and a main reason is that he doesn’t like the company’s content moderation.

A peculiar fact about our modern public sphere is how much its borders depend on the whims of a few companies and their billionaire owners. A handful of people—mostly men and mostly in Silicon Valley—decide whether Russian state media should be allowed to have social-media accounts, whether a controversial post about the coronavirus can be amplified to millions of people or will be taken down, and whether the former president of the United States will keep or lose his most direct line to the global public. The executives who kicked Donald Trump off Twitter, Facebook, and YouTube early last year could’ve made those judgments by coin toss and no one could have done anything about it. The deliberation about whether to let him back on if he runs for president again in 2024 could be just as arbitrary. Millions of similar decisions—of differing levels of consequence—are made every day.

Our public sphere is governed by almost entirely unconstrained private power. As the internet has become ever more centralized on just a few major platforms, the impact of those companies over every aspect of our lives—politics, culture, the very way we speak—has kept on growing.

That might not seem so bad when content-moderation decisions come out how you want them to. Many on the left celebrated platforms’ ability to banish Trump with a few clicks. Many on the right believe they are unfairly targeted by left-leaning Silicon Valley executives and may celebrate a more freewheeling Twitter if Musk gets rid of many of its content-moderation rules. But that’s shortsighted. Ultimately, private power will always protect private power and not public interests.

Beyond the stray hints he’s offered in tweets, SEC filings, and interviews, Musk hasn’t given much detail about his vision for Twitter. But if he thinks it can exist without extensive content moderation, he is in for a shock. A universal rule of user-generated platforms is that every one of them has to moderate posts once it reaches a certain size. A platform that refuses to dirty its hands by taking down content will soon become flooded with scammers, porn, terrorist recruiters, and, sometimes, literal shitposts. And its user base, its advertisers, and the other tech companies it relies on to operate won’t like that. Parler, Gettr, and Reddit all learned this lesson the hard way. That’s not even to mention the tightropes platforms have to walk in dealing with governments around the world that are ramping up pressure on platforms to submit to their will, often at the cost of their citizens’ free-speech rights.