Public ownership does not solve censorship. See: the CCP.
Effective policing does not solve censorship. The police will be tools of whoever and whatever is funding them.
The only way to combat censorship is through decentralised and distributed platforms that are made publicly immune to takedowns, censorship, and prosecution.
It astounds me that people are happy to accept that free speech in the US only applies in public spaces, while handing over control of the best places for spreading information to private companies. What's the point in that? "Free speech only applies to public space! Private companies can censor who they want! proceeds to make sure the information superhighway is entirely owned and controlled by private companies".
But public control doesn't work either. We've already seen government around the world censoring information in the "public interest".
Decentralisation, and distributism are the only ways.