Medium’s behavior here is absolutely reprehensible but also predictable: we should always assume that owners of centralized content regimes will abuse their data serfs.
Really what software developers should be doing is making it easier for each of us to rule our own content. The people who built Medium (and other centralized data serfdoms) are doing a disservice to humanity. They should be liberating the individual not subjecting him to control by unaccountable elites.
It’s possible that Medium might, in the face of enough criticism, reverse course on this, but the principle is what matters: they are building something that should never have been built.