The author has some control over it, he may, for instance, issue takedown notices, and some may argue that if the pirate website didn't receive a takedown notice, the author didn't do his job protecting his IP and was, therefore complicit. The author may respond that Amazon itself allowed piracy. It may take lengthy legal battle that no one but lawyers will win.

Also, contract law varies a lot by country. What is allowed in the US may not be allowed in France for instance, adding an extra layer of complexity.