Originally Posted by Harmon
Neither Scalzi nor his publisher can make something that is illegal (marketing DRM stripping tools) legal by permitting you to do it on their books.
But the law does not make it illegal to acquire DRM stripping tools, so if you acquire them, what Scalzi & the publisher are doing is telling you that they won't sue you for stripping. They could still actually sue you, but they would lose (1) because it's not illegal for you to strip the DRM from a book you legally acquired from them, and (2) even if that turned out not to be true, you could defend yourself under a legal doctrine called "detrimental reliance," basically meaning that you relied on their promise so they can't take it back.
Technically speaking, Scalzi might be violating the law for linking to the tools, since he's helping to distribute them in a commercial context. Certainly if I were his lawyer, I would tell him not to link. The way this should be handled is for everyone who bought a DRMed ebook to be sent a new, DRM free copy by the publisher.
I do think Tor was also on board.
The tools have to exist in order for DRM to be stripped. If we go by just the DMCA exception saying that DRM can be stripped in a certain case, then the tools have to be written so they can be used to strip the DRM. So how can it be illegal to write the tools if it's not illegal to use them?