On September 27th, 2018, the behemoth online discussion forum Reddit “quarantined” 23 of its “subreddits,” subsidiary discussion threads within the larger site. Internet communities “dedicated,” in Reddit’s words, “to shocking or highly offensive content” would be placed on a kind of probation. Quarantined subreddits are disallowed from generating ad revenue. They cannot be found in searches, and it becomes impossible to see how many members subscribe to them. Quite a few of those quarantined in September were subsequently banned altogether.

All subreddits are titled according to the format “r/[nameoftopic],” and the September list included such appalling titles as “r/watchpeopledie” and “r/whitenationalism.” As a group they were ideologically quite diverse: “r/FULLCOMMUNISM” was also put on the watch list, as was “r/theredpill,” a thread infamous for hosting the various fractious splinter groups known collectively as the “Alt-Right.”

Reddit is not the only platform faced with charges of enabling online extremism, and not the only one to take measures meant to blunt them. The censorship of views deemed unpalatable by social media companies is now a matter of regular and tendentious attention, most recently because Facebook founder Mark Zuckerberg was called to testify before Congress on October 23rd of this year. The House raised the same question that the Senate did during Zuck’s appearance there in April of 2018. Namely: what right does Facebook have to make decisions about the sorts of content you ought and ought not to consume?

As a legal matter, the answer seems to be: Facebook (or Reddit, or Google, or Twitter) has no such right, if it wants to continue enjoying the extraordinary protection from libel law that is afforded to platforms (purveyors of content) as distinct from publishers (curators of content).

But from a purely philosophical standpoint, as a measure of the zeitgeist, Reddit’s practice of quarantining actually speaks to something deeper than the law. A quarantine is something you do when you do not want something—usually a disease—to spread. To “quarantine” ideas therefore implies what you are really worried about is not that those ideas are false, but that they will catch on. Reddit’s choice to conceal membership statistics for quarantined threads betokens the same anxiety: if people know that some view or set of views has a substantial following, perhaps they will start to wonder whether there might just be something to it.

Reddit is therefore not merely trying to weed out falsehoods or incitements to violence. Such projects are already dubious enough when undertaken by an overwhelmingly liberal Silicon Valley in tandem with leftist “fact-checkers,” who are perfectly willing to smear even conservative satire with risible charges of misinformation.

But quarantining isn’t actually framed in those terms. It’s predicated on a complete unbelief in the basic principles underlying the marketplace of ideas. From John Milton to John Stuart Mill and right on into the American republic, the governing consensus has been that free men and women get to decide for themselves what they find convincing. This was the reasoning behind 1977’s National Socialist Party of America v. Village of Skokie, wherein the Supreme Court famously allowed even Nazis to demonstrate in public.

We believe—or used to believe—that if the public is empowered to consider all the options then the best ideas will win and the truth will out. Reddit’s owners have shown that they simply do not think this is the case: they believe that good ideas, as defined by them, need a thumb on the scale to help them compete in the market.

Evidence would suggest that they are actually wrong about this—before being quarantined, all 23 of the threads targeted in September had (on the unlikely assumption that none of them shared any subscribers in common) a collective membership of 1,363,282. That’s 0.42% of the U.S. population.

But let’s imagine that a group which Reddit considered heinous did show signs of gaining real traction. Would that not suggest that the beliefs espoused by that group deserved a hearing, not a health warning? Shouldn’t people be allowed to get swayed, if they are swayed, even by arguments which their “betters” deplore?

Discussing the Zuckerberg hearings, 60 Minutes host John Dickerson said at Slate this week that Facebook should nix posts which present “characterizations and framings and elevations of certain issues that distort political reality…but that don’t have a specific fact that can be pinpointed…to remove them.” Emily Bazelon, in agreement with Dickerson, endorsed censorship of such material “even if it’s not completely false.” Jeff Zucker, president of CNN, went so far as to suggest that Facebook should “sit out” the 2020 election and muzzle political advertising entirely, “given what happened in 2016.”

There is reasonable discussion to be had about how to navigate and manage our new informational ecosystem. But at this point, that discussion is no longer being framed by the Left in the terms essential to free speech. Leftist dogma is instead threaded through with an extremist rhetoric of suppression and control. That control—tyrannous and self-satisfied as it is—should be resisted at every turn.