Adversarial interoperability is necessarily going to involve workarounds. The straightforward path has been blocked. A hassle barrier is very nearly as effective as an outright block (which is why Google have one for IMAP access, the want most people trapped in webmail), and draws much less protest from techies.
That said, the Russian hassle barrier to using DC currently seems way too effective, and a tiny oligopoly of permitted servers is far too easy to subject to centralized control.
An encrypted channel to access arbitrary mailservers would be a more elegant solution.