In the wake of the protests and tragic violence at the United States Capitol last Wednesday, Parler, the popular alternative to Twitter, is facing an unprecedented crackdown from its competitors. In the span of 48 hours, both Apple and Google announced they would be removing the app from their smartphone app stores. Shortly thereafter, Amazon Web Services announced it would stop hosting Parler, thus also wiping out its web component.

Signaling his thanks, Twitter CEO Jack Dorsey—who calls his platform one that stands for "free expression" and "empowering dialogue"—tweeted out a heart emoji when Parler no longer showed up on Apple's list of popular apps.

The rationale given by all these Big Tech behemoths is that Parler doesn't do enough to moderate the violent threats its users make on its platform. This is rich, coming from companies that host and circulate Facebook and Twitter, where violent threats proliferate on a daily basis. Twitter has even gone to court, on free speech grounds, to protect the use of its site for organizing protests—even ones where conduct is disorderly.

Over the summer, many Black Lives Matter protests were organized on social media. Many of those protests later turned violent. All told, this summer's riots, which spanned 140 cities, caused more than $2 billion in damage and resulted in at least 25 deaths. Has anyone undertaken an investigation into the links between those riots and social media?

Moreover, when it comes to their own behavior, these companies deny that any links could possibly exist between content moderation and offline harm. Last year, their representatives sat on stage at a Department of Justice workshop and insisted that what is said or circulated on social media isn't their fault—they just amplify reach. Streaming a murder, for example, isn't at all the same as committing it, they asserted. They've testified before Congress that their platforms should not be held in any way responsible for one image of a child's sexual abuse circulating more than 160,000 times. Law enforcement should just do more, they've argued.

So to condemn Parler for "not doing enough"—to make them liable, in other words, for any violence that might result from what people say—directly contradicts the standards these platforms hold for themselves, not to mention the standards they demand the U.S. government hold for them. Section 230 protections for me, but not for thee.

But this clearly collusive behavior sets other troubling precedents in the market. For years, pro-Big Tech lawmakers, pundits and analysts have told those unhappy with the major platforms to "build your own" Facebook or Twitter. "Conservatives are ignoring the rest of the internet," scoffed one libertarian in August.

So John Matze, the founder of Parler, went and actually did it. He built his own Twitter. Yet those same pro-free market conservatives and libertarians mocked him and his product. And now, when that product is under threat from collusive market behavior for obvious political reasons, they have gone completely mute.

Social media site Parler is indefinitely offline due to action by Apple, Google and AmazonHollie Adams/Getty Images

"Build your own," it turns out, really was nothing more than a slogan with no intellectual commitment behind it. It was a semantic quip that deployed the rhetoric of the free market to protect entrenched corporate interests.

"Build your own," in other words, until it actually challenges Facebook, Google or Twitter.

As a practical matter, moreover, what is happening to Parler has rendered the "build your own" argument moot. Conservatives can build as many alternatives as we want, but should they grow at all powerful, the speech police will come for them—and remove every piece of infrastructure a growing company needs in order to access a mainstream audience.

Big Tech has both market control and narrative control. And as has been proven time and time again, they will form a cartel to aggress against any competitor who dares to host a diversity of views or threatens their market dominance in any way.

This behavior cannot be tolerated in a free market—much less in a free society. A free market depends on innovative competitors being able to win on their merits, and a free society depends on the open exchange of ideas.

Conservatives can continue to marginalize themselves in tiny ghettoes of the internet, but that does not really represent what Americans understand "free speech" to be. Free speech is not just about who speaks—it is also about who hears. And when three or four companies control the virtual public square, their power to silence viewpoints and information in completely unaccountable ways is distorting and unraveling our society.

Laissez-faire conservatives and libertarians—anyone who cares about liberty, really—should be speaking out in force against corporations colluding to silence competitors. Whether you disagree with Parler's content moderation policies or not, a society that tolerates this level of corporate control over speech, information and free thought is one where self-government—where the people rule—will quickly be sacrificed for something resembling a corporate plutocracy.

Big Tech's control has been evolving slowly. But after last Wednesday, the floodgates have truly been unleashed. Everything conservatives say they stand for—free thought, free speech and free markets—is now under threat. Parler is just one company, but it is very much a proxy for the battle that is to come. And based on the silence from conservatives and libertarians in D.C., we are ill-prepared for the fight that is now at our doorstep.

Rachel Bovard is senior advisor to the Internet Accountability Project.

The views expressed in this article are the writer's own.