Isn't that actually the point? Megacorps like Zuck's are beholden to the government to not break them up or pass laws they don't like, so they bend the knee whenever it's users or free speech taking the hit. Evidence of this not happening would be a non-corrupt government that breaks up the companies or repeals the laws that prop up their market dominance instead of the government taking them up on the quid pro quo.

To prevent this you need social media to not have central gatekeepers in a position to censor things to begin with.