People invest massive amounts of time to build a following and create content on those platforms. It seems reasonable to ask that it can't be taken away from them at a whim. However, in theory, they should have read the contract before entering it. If they accept those terms, perhaps they should have to live with it.

An analogy would perhaps be a musician signing a contract with a record label? I think they expect some reciprocity, like if they owe three albums to the label, the label also owes them marketing for those albums.