This is entirely false. The books can still be put up as an .epub at a URL on any of thousands of servers that can be accessed by the entirety of the internet-connected Earth. Such hosting service can be obtained in 5 minutes for a pittance, and will easily serve tens of millions. For slightly less than a pittance you can serve the file to billions.
If Facebook starts censoring posts or private person-to-person DMs with your URL in it, we have another discussion to have, but until that time this is just the normal freedom-of-association choices associated with being unpopular. Amazon sucks for doing this, to be sure, but the TFA is committing a worse offense: claiming inaccurately to have been banned.
There has never been a time where it has been easier or cheaper to publish to literally billions-with-a-b.
Apple made it so you can't even type a Taiwanese flag emoji if you are using an iPhone in the PRC.