through terminals that have no automation interfaces…but there are no tools that bots could use

If people still have access to general computation (for example a computer at home), somebody could just run a bot at home, ask beforehand what the bot wants to post, then go to the terminals.

One the other hand if we assume it’s feasible to ban all general computation, then you can achieve all three “anonymous”, “available to everybody”, and “free of bots”. Just use the postal mail system.

any system that issues an access token to an individual cannot be anonymous if revocation is to be meaningful.

If a government (or any other authority) keeps track of whether they issue someone an ID, then they must also have the ability to connect IDs to individuals.

Simple idea off the top of my head, building off GNU Taler. Citizens are allowed to get one Taler wallet from a central authority. The wallet is pre-loaded with $1 of a special currency. That currency can only be used to buy a social media account from the government for $1. Since GNU Taler transactions keep the buyer private, the government doesn’t know who bought which account. The government can still ban accounts, without knowing who is behind them.

And sure somebody could give their account to somebody else. But the system still satisfies the “anonymous” and “available to everybody” requirements.

Edit: formatting