It took the shock of Trumpism to finally awaken complacent liberals to a whole raft of ugly truths about twenty-first-century America—and about the last truly great American invention, the unregulated internet. Somewhere during primary season in 2016, it began to dawn on us en masse that social-media platforms like Facebook, Twitter, and Reddit—the kinds of places liberal utopians and Silicon Valley hucksters had long assured us would be magical boons to an “open society” and the progressive cause—had morphed into far more potent delivery systems for intolerance, terrorism, white supremacy, and right-wing fake news. And when the “alt-right” brought its race war to Charlottesville earlier this month with horrific results, it became clear to one and all that what began as an Internet phenomenon had become a menace to society IRL.

It’s not as though we hadn’t been warned. Social scientists have been telling us for decades that terrorism and extremism grow out of social networks. In 2007, legal theorist Cass Sunstein eloquently anticipated the ill effects of Internet filtering on our democracy in a prescient essay that he expanded into a cautionary book called Going to Extremes: How Like Minds Unite and Divide. “As a result of the Internet, we live increasingly in an era of enclaves and niches,” he observed, and “enclaves of like-minded people are often a breeding ground for extremist movements.” Such movements once had to involve a measure of physical human interaction, and access to information (and misinformation) that could be hard to come by. With the Internet, the process of radicalization has been accelerated many times over.

During the campaign, YouTube was mostly exempted from our belated hand-wringing, soul-searching, and boycott-threatening, despite the platform’s massive and ever-expanding reach: 1.5 billion viewers a month and counting, with 400 new hours of video uploaded by users every minute. That began to change in the backwash of Trump’s election. Earlier this year, mainstream news outlets started reporting what should have long been obvious: Good ol‘ lovable YouTube was hosting millions of hours of well-watched intolerance, much of it far uglier than anything Bill O’Reilly, Sean Hannity, or Mark Levin could get on the air. “Yes,” wrote BuzzFeed reporter Joseph Bernstein, “the site most people associate with ‘Gangnam style,’ pirated music, and compilations of dachshunds sleeping is also the central content engine of the unruliest segments of the ascendant right-wing internet, and sometimes its enabler.”

Once reporters and left-wingers started venturing out of their own YouTube bubbles and sniffing around the rest of the platform, they found a house of anti-democratic horrors—one that seemed to contain an infinite number of rooms. Was it merely a coincidence, folks began to ask, that when you searched for “Holocaust,” the top 10 results directed you to Holocaust-denying content and anti-Semitic screeds? Was it just happenstance that the racists, misogynists, anti-Semites, and conspiracy-mongers of the right, from Alex Jones to wildly popular but relatively obscure propagandists, had made YouTube their digital home?

It was hard to blame YouTube, exactly. Unlike its owner, Google, with its “Don’t Be Evil” code of corporate conduct (nixed in 2015 by Google’s holding company, Alphabet), YouTube’s original motto was “Broadcast Yourself.” Until recently, the platform was unusually honest about what it’s there for; as Christos Goodrow, its “director of engineering for search and discovery,” told Business Insider in 2015, “We believe that for every human being on Earth, there’s 100 hours of YouTube that they would love to watch. And the content is already there. We have billions of videos. So we start with that premise and then it’s our job to help viewers to find the videos that they would enjoy watching.”