Unlike many libertarians, I think that big-tech is indeed acting unconstitutionally. That's because, I don't think companies like Facebook are acting independently, but as an agent of the state. It's no different than if the deep-state hired private contractors to intimidate and silence me. The fact that they are private actors is irrelevant.
Also, the left tries to use the fact that they are private actors as a bludgeon instrument to shut us up. But the truth is, even if that is so, we still have a right to call them out as being assholes who deserve to get their ass kicked.
However, unlike many other people, I personally think big tech is doing us a favor. Alternative platforms, and decentralized technologies have sprung up everywhere. All of these entrenched tech companies have the unenviable task of shutting down the free flow of information just as the information age is blowing up out of control. It is not only unworkable, but as decentralized technology improves and the size of the network grows, the cost of trying to impose internet censorship grows exponentially.