I just don't want to dispel this idea of a social contract as it simply doesn't exist.
Actually, it does exit. There can be no blockchain without a social contract around it. It can be implicit or explicit but it exists in some form. You can read more about it here. Ethereum is a good case showing what happens when you neglect this issue.
It's a problem I raised a couple of months ago - I argued that sooner or later we will be in trouble if we don't come up with some sort of more formal constitution or manifest or social contract. As a result, @dantheman has even prepared a draft but the issue was then dropped as focus has moved to development.
How can any contract exist without the signatures and mutual agreement of all parties?
In case of Steem, the contract is declared by the founders' public statements and the whitepaper. For example: immutability of the blockchain as far as censorship is concerned is one of the publicly declared axioms for Steem.
But you do have a valid point - founders' intentions should have been written down long time ago and each new user should have been asked to acknowledge them when registering a new account.
Without having this in place we ask for trouble. It's just a matter of time when this community hits a big dilemma and splits. A more formal social contract cannot fully prevent it (as it's hard to predict all future dilemmas) but at least this is the most we can do. Also, it's easier to decide which part of the split is more "classic" and sticks to the original intentions of the founders.