I'd like to be devil's advocate here - in case of Orwell books, given that publisher had no rights for them, the situation is similar to the selling of stolen goods.
Sure, but if the local grocer realizes he sold me stolen eggs, he doesn’t get to send his henchmen to my house in the middle of the night to steal them back.
The amazon/Orwell fiasco was the moment I decided to never buy a kindle and steer clear of anything with drm.
I actually agree that it's a situation that's unrelated to whether the retailer is selling licenses or copies of the book, which is what my original comment is about. I do think that Amazon could have handled the situation better though. It probably would have been to everyone's benefit for them to work out the issue with the rights holders instead of passing their mistake forward to their customers. They may have tried to do that behind closed doors and failed, of course.