[1] https://en.wikipedia.org/wiki/Government_of_New_York_City
[2] https://en.wikipedia.org/wiki/New_York_City_Police_Departmen...
No society with numbers north of somewhere in the two digits works without some kind of rules, administration, and enforcement. I'll bet you there are at least half a million people staffing courts in the US, maybe even a full million, and probably an equal number of law enforcement officers, and that doesn't get to public and private attorneys which is probably another million.
Which means something like 1% of the population of the US is probably involved in just administering the laws of society.
Now, maybe for a society where the limits of how people interact is communication you could get away with lower overhead. But that's going to be a constant factor of the same underlying dynamic.
Also, we've done the same damn thing with freedom of discourse that we have with almost every other liberty in the US: we turn it into a thought-stopping cliche and glide on treating it as an indulgence rather than investing in thinking about the limits, edge cases, and responsibilities.
Ofc, Facebook does not provide nowhere near as many services as a city would, but ... it still seems to me that current user:moderator ratio is very obviously insufficient.
In the early 2010s, this sorta worked, because the effects on real world politics were insignificant. Now everyone looks at their fingers and they have a very underinvested infrastructure and no clear idea what to do.