But in a way, what happened between the Steem witnesses and some guy called Justy or something like that was exactly what would happen when an entity, a person or a business and their account is under suspicion and investication by a governing central banking entity, which also happens to be our government, the witnesses.
In our defense those actions were more or less democratically chosen and put into use, as in decentralized. But it can still be considered an action by the government of the blockchain.
Now in a comparison, what this same man or business is doing now on the exact same blockchain to the investors therewithin is more akin to a dictator acting as the central bank and the government all in same entity with no democratic oversight. That's the opposite of decentralized. Now this can also be considered a governmental action of sorts, but this one is in the hands of one man. That is dictatorship in a nutshell.
Yes there are boundaries to what a government can and can't do, but a government can oversee banking whenever it is accepted and requested by those who in turn oversee the government, the voters.
In the case of the blockchain, we all have a direct, real-time monitoring (and controlling) capacity over every transaction. The blockchain is public and fully transparent. So we can act as a government, and a central bank at the same time.