It's an interesting argument. I will say though, that wouldn't the government being forced to break apart major technology companies be a form of control in and of itself?
Consider the following. Facebook grows to become the only website on the internet. Everyone spends their time on Facebook-owned services. Social media is a niche platform, moreso than web browsers, operating systems, Standard Oil. It is a lot easier to switch websites than an oil company. Consequently, everyone becomes subject to Facebook's moderation. But, the internet still exists, and I can create a website no problem, except nobody would use it. That happened when Reddit users attempted to jump ship to Voat years ago.
So now the government decides Facebook is too big. They want to break it apart into smaller sub-forms, presumably with the intent of bringing back competition and allowing diversity of expression. Only problem is a) the government decides which rules are arbitrary and which are not, not the market and b) now we have a bunch of medium-sized players, each with their own set of the exact same rules because they're all competing with eachother. It's like having five big banks instead of one. You're going to get the exact same service and restrictions, with very slight variations.
Part of the issue with freedom of speech is it will always be a nebulous concept. Technically, you are free to do whatever the hell you please. The only laws binding you are the physical constraints of this reality. Jump off a building type shit. But then you have laws, which are nebulously defined in themselves as they're always subject to interpretation (is yelling "I have a gun?") free speech? What if I'm on stage performing a play? At this point the community determines what's allowed and what isn't, and the whole artifice essentially breaks down.
So you have a community of legal interpretation deciding what is or isn't capable of getting other human beings to throw you in jail. That's the only legitimate-use-of-force (thanks Weber) way to make somebody shut up. But, society, you know, the animal carcass you carry around in the present moment, one doesn't say or do certain things because it will make your life hell. If you wear a clown costume to work, if you dye your hair a funny colour, if you become an advocate for unpopular opinions or viewpoints, you might find your most valuable resource - other human beings no longer want to associate with you. That creates lost profits, reduced income, fewer opportunities for advancement, social isolation, inability to find romantic partners, even worse, possible institutionalization or death.
In practice "freedom of speech" really means, "freedom to say what you want provided it doesn't make you lose your food, water, and shelter." Wanting more than that creates further limitations. And if Facebook can create more jobs by blocking certain speech, who is free?