Castalia House publishes non-converged fiction and non-fiction. SJWs within Amazon have gone after them in the past over a book called Corrosion. Corrosion is a shot at a little gamma author John Scalzi’s Collapsing Empire book. Scalzi got a fat contract for essentially copying Heinlein’s style (iirc), and spends more time spurging than writing.
It is another attempt to deplatform the Right. Something Amazon had been relatively good at avoiding. Hopefully this incident is just another “lone wolf” SJW.
I just checked and Amazon is selling the obvious and deceptive Transformers rip off “Transmorphers” still so their rationale for nuking this publisher seems a bit fishy. Then I saw that these guys were on the right side of the “Sad Puppies” thing and it all became clear: the lefties targetted them in revenge. Most SciFi is unreadable SJW nonsense now so I haven’t followed it closely but I do know about the Sad puppies stuff and yeah, now it makes sense.