I think the arguments are crazy. The books are bought and sold. There is no license to use the books. Once the book is bought it is the property of the user.
What happened maybe similar to Fictionwise. Fictionwise awhile ago ended a relationship with one of the publishers. I lost a few books when I bought the iRex Digital Reader with a new MobiPocket ID. I could still read these particular books on the old reader but was unable to move them to the new reader. In Amazon's case there will never be a new reader issue because each new reader can be associated with the Amazon account if I got that right and the old one can be removed. It put Amazon in a difficult situation but still I believe they had no right to pull the book.