Give a man a fish, and you feed him for a day. Teach a man to fish, and you feed him for a lifetime. It's better to train society and individuals to take what is out there and teach them how to process it than to institutionalize them to trust "experts". Even today, before you take medical decisions, you have to trust your own instincts on what is the best for you. Yeah, those so called experts, won't make the right decisions.
Handing over arbitration of truth is an extremely foolish idea. We might as well have dictatorship and let "elders" decide for us and give up on democracy. Doing _something_ is not a virtue by itself, it has to be meaningful and many times you just have to pause and do _nothing_.
Division of labor does not necessarily mean total centralization.
Which in turns looks very much authoritarian and undemocratic.
As for self-censoring. Yes, that can be an issue. You picked racial slurs because that makes self-censoring seem morally acceptable, you're biasing the scenario in your favor. What about protesters calling for violence against an oppressive government? That would commonly be considered a violation of "community guidelines" on social networks.
My issue with social networks is that they amplify without providing contrast. Often there's viral, in-the-moment content which is technically truthful but doesn't provide context. Getting the "yes, but ..." replies that add nuance or rebut the framing would be helpful. Distinguishing and filtering by affirmative vs. conterarguments would be helpful in controversial topics. This doesn't require fact-checking by an arbiter of truth, just a way for people to select which responses they see.
Today's world is vastly more complex than it was in our ancestral environment, and that makes assessing truth very hard. It's not possible for anyone to directly access all primary sources, so we have no choice but to set up some kind of division of labor in the assessment of truth. Scientific peer review is one example of such a division of labor. We trust peer reviewed publications not because peer review is flawless, but because we have to do something to triage the myriad firehoses of information that exist in today's world, and peer review is the best we've been able to come up with so far.
Handing over the arbitration of truth to unaccountable private corporations is, like peer review, far from optimal. But we have to do something or those who are out to deliberately deceive to advance their political agendas will win. It is always easier to destroy than to create, and it is easier to promulgate a well-crafted lie than the truth. Those are the facts on the ground that we as a society have to grapple with. It's a hard problem and none of the solutions that have been proposed are optimal. But that's no excuse not to try to do something. If we don't, society will descend into chaos and authoritarianism. Fact checking by social media platforms is far from optimal, but it's a hell of a lot more likely to advance democracy than survival of the fittest con man.