But it's copyright laws that allowed this to happen legally. How should Amazon decide which legal rights publishers get to keep and which rights they don't? And are corporations the right entity to decide what is moral and what isn't? Would you blame chain manufacturers for slavery, or the laws which make slavery legal?
This whole thing goes to show how DRM can negatively effect a consumer
But DRM is just the mechanism for enforcing what people perceive as immoral laws. If books were removed once-bought in a way without DRM, surely people wouldn't be any less outraged, would they?
Legally, you can write a contract that says Amazon has the right to break into your house and repossess books they've sold you that they no longer have the rights to. Just because it's legal doesn't mean it's good business.
Could you cite the law which would make such a contract enforceable?
Amazon is using DRM and EULAs to accomplish things that people would not normally expect when thinking about a book. Amazon wants people to think of the things they "buy" on their kindle as books, but this incident demonstrates that they are not.
Amazon is (probably) legally within their rights to do what they did according to the kindle contract, but that doesn't mean it's good for business.
Just because people expect to have certain rights, doesn't mean they do. If people expect to have rights (to keep copyrighted material indefinitely) that the law of the land takes away from them, the problem isn't with the mechanism through which that law is implemented, it's with the law itself!