It is worth keeping in mind, however, that when it comes to Mastodon (federated alternative to Twitter) - federation blocklists adopted by instance admins – and enforced unilaterally on their users – beats the spirit of it all, because many popular instances that adopt IdPol-fested policies end up clustering, and blocking other (non-IdPol adopting) instances en masse. See jointhefedi.com for a list of servers. The problem here is that moderation and censorship is still done by centralized parties (ie. instance admins) rather than voluntarily by the individual people themselves. Any centralized and unilateral enforcing of speech online is likely to become corrupt no matter the intention. Mastodon instances are also more likely to suffer from activist pressure than Twitter.
The core problem here is the monolithic nature of these social networks, not their size per se. The solution is decentralization,* making it impossible for there to be a large monolithic network thus discouraging any form of universal group-think, for there will be no such universal group.