Agreeing to use social consensus to enforce the protocol doesn't give a green light to using it to change the protocol. As the DAO and the BCH hard fork showed,

Agreeing to use social consensus to enforce the protocol doesn't give a green light to using it to change the protocol. As the DAO and the BCH hard fork showed, having an objective proof of work consensus protocol doesn't protect the blockchain from a social consensus to change the protocol. That being said, depending social consensus to determine what happened could make it more likely that a faction will use it to determine what should have happened. I personally don't think it will make it very likely, given the inertia of the original chain, but we'll see.