Nobody can shut down a blockchain when setup right; Even the Steem blockchain; Steem has witness nodes running the blockchain and some of them are not in the USA, they are in Europe and Asia, out of control of USA government.

Anonymity drives more illegal actions, and drives the 'hunt of' since the most important element to keep a group of people, a community alive, is taken away: "Social Control".

More importantly, at Steem indeed a few can shut the mouths of almost anybody! Since most of the users are anonymous at Steemit, including those big whales, it is easy to go into war with some others on the platform since nobody is able to find the real person behind an account going to war.