The information is stored on the blockchain and other people can create their own gateway websites into that blockchain. So while Steemit.com can attempt to censor or whatever, the other gateways into the system would still see it.

As for the other part of how it works, any closed entropy system is technically issuing shares of a private company in the form of a permissioned ledger. However, the act of posting to tap into "shares" of that company via steempower kinda reverses that back to a somewhat open entropy system again.

You could make the argument that the system functions in a permissioned state because anything with deterministic block production has to be funneled through preset choke points, but Bitcoin itself also seems to have similar choke points in the form of pools that don't change that often.

Everything in cryptocurrency is just trade offs with probably no real way to significantly improve upon the decentralization in Bitcoin. Meaning, everything is just KINDA decentralized.

My statement on PoW is, Satoshi didn't solve Byzantine generals, so one confirmation is obviously useless. The only reason more than one confirmation is useful is because you assume the cost to attack is too high to permanently enact on an infinite timeline.